牛客专题训练

专题链接

1. 顺序结构习题

牛客竞赛语法入门班顺序结构习题

1001 这是一道签到题（多行字符串）

可用\拼接多行字符串

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#include <iostream>
using namespace std;
int main()
{
    cout << "zhe\n\
shi\n\
yi\n\
dao\n\
qian\n\
dao\n\
ti" << endl;
    return 0;
}

1002 排列式（全排列）

c++可以用next_permutation()生成下一个排列

思路一：暴力遍历所有数字判断是否有重复数字，再检查式子是否符合乘法等式，超时。

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#include <iostream>
#include <cstring>

using namespace std;

void check(int x)
{
    int cnt[10];
    memset(cnt, 0, sizeof cnt);
    for (int a = x; a; a/=10) ++cnt[a%10];
    for (int i = 1; i < 10; i ++) if (cnt[i] != 1) return; 
    int a = x / 100000;
    int b = x % 100000 / 1000;
    int c = x % 1000;
    if (a == b * c) printf("%d = %d x %d\n", a, b, c);
    b = x % 100000 / 10000;
    c = x % 10000;
    if (a == b * c) printf("%d = %d x %d\n", a, b, c);
}

int main()
{
    for (int i = 100000000; i < 1000000000; i ++) check(i);
    return 0;
}

思路二：全排列，AC

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#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;
const int N = 9;
int a[N] = {1, 2, 3, 4, 5, 6, 7, 8, 9};

int get(int i, int j)
{
	int ans = 0;
	while (i < j) ans = ans * 10 + a[i++];
	return ans;
}
void check()
{
    int a = get(0, 4);
    int b = get(4, 6);
    int c = get(6, 9);
    if (a == b * c) printf("%d = %d x %d\n", a, b, c);
    b = get(4, 5);
    c = get(5, 9);
    if (a == b * c) printf("%d = %d x %d\n", a, b, c);
}

void dfs(int idx)
{
	if (idx == N) check();
	for (int i = idx; i < N; i ++)
	{
		swap(a[idx], a[i]);
		dfs(idx + 1);
		swap(a[idx], a[i]);
	}
}
int main()
{
	dfs(0);
    return 0;
}

方法三：next_permutation()函数

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#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;
const int N = 9;
int a[N] = {1, 2, 3, 4, 5, 6, 7, 8, 9};

int get(int i, int j)
{
    int ans = 0;
    while (i < j) ans = ans * 10 + a[i++];
    return ans;
}
void check()
{
    int a = get(0, 4);
    int b = get(4, 6);
    int c = get(6, 9);
    if (a == b * c) printf("%d = %d x %d\n", a, b, c);
    b = get(4, 5);
    c = get(5, 9);
    if (a == b * c) printf("%d = %d x %d\n", a, b, c);
}

int main()
{
    while (next_permutation(a, a + 9))  check();
    return 0;
}

1003 小飞机

直接打印。

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#include <iostream>
using namespace std;

int main()
{
    cout << "     **     " << endl;
    cout << "     **     " << endl;
    cout << "************" << endl;
    cout << "************" << endl;
    cout << "    *  *    " << endl;
    cout << "    *  *    " << endl;
    return 0;
}

1004 学姐的”Helloworld!”

看清楚，一般复制字符串过来比较稳妥。

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#include <cstdio>
using namespace std;

int main() {
    printf("Helo word!");
    return 0;
}

1005 乘法表

格式输出

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#include <cstdio>
#include <iostream>
using namespace std;

int main() {
    for (int i = 1; i <= 9; i ++)
    {
        for (int j = 1; j <= i; j ++)
        {
            printf("%d*%d= %d ",j, i, j * i);
        }
        printf("\n");
    }
    return 0;
}

1006 KiKi学程序设计基础

注意输出\n的时候要转义\

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#include <cstdio>
#include <iostream>
using namespace std;

int main() {
    printf("printf(\"Hello world!\\n\");\n");
    printf("cout << \"Hello world!\" << endl;");
    return 0;
}

1007 疫情死亡率

百分号输出用%%

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#include <cstdio>
#include <iostream>
using namespace std;

int main() {
    int a, b;
    cin >> a >> b;
    printf("%.3f%%\n", b*100.0 / a);
    return 0;
}

1008 爱因斯坦的名言

难受，cout输出%时不需要转义

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#include <cstdio>
#include <iostream>
using namespace std;

int main() {
    cout << "\"Genius is 1% inspiration and 99% perspiration.\"" << endl;
    return 0;
}

1009 字符串输出1.0

没啥。

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#include <cstdio>
#include <iostream>
using namespace std;

int main() {
    cout << "Welcome to ACM / ICPC!" << endl;
    cout << "Welcome to ACM / ICPC!" << endl;
    cout << "Welcome to ACM / ICPC!" << endl;
    return 0;
}

1010 牛牛学说话之-整数

整数输入输出

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#include <cstdio>
#include <iostream>
using namespace std;

int main() {
    int a;
    cin >> a;
    cout << a;
    return 0;
}

1011 牛牛学说话之-浮点数

浮点数输入输出

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#include <cstdio>
#include <iostream>
using namespace std;

int main() {
    double a;
    cin >> a;
    printf("%.3f", a);
    return 0;
}

1012 牛牛学加法

加法。

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#include <cstdio>
#include <iostream>
using namespace std;

int main() {
    int a, b;
    cin >> a >> b;
    cout << a + b;
    return 0;
}

1013 牛牛学除法

整除

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#include <cstdio>
#include <iostream>
using namespace std;

int main() {
    int a, b;
    cin >> a >> b;
    cout << a / b;
    return 0;
}

1014 牛牛学取余

取余

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#include <cstdio>
#include <iostream>
using namespace std;

int main() {
    int a, b;
    cin >> a >> b;
    cout << a % b;
    return 0;
}

1015 浮点除法

整数浮点除法。

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#include <cstdio>
#include <iostream>
using namespace std;

int main() {
    int a, b;
    cin >> a >> b;
    printf("%.3f", a * 1.0 / b);
    return 0;
}

1016 计算带余除法

整除、求余

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#include <cstdio>
#include <iostream>
using namespace std;

int main() {
    int a, b;
    cin >> a >> b;
    printf("%d %d", a / b, a % b);
    return 0;
}

1017 K蝴蝶

减法

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#include <cstdio>
#include <iostream>
using namespace std;

int main() {
    int a, b;
    cin >> a >> b;
    cout << a - b;
    return 0;
}

1018 水题再次来袭：明天星期几？

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#include <cstdio>
#include <iostream>
using namespace std;

int main() {
    int a;
    cin >> a;
    cout << a % 7 + 1;
    return 0;
}

1019 开学？

好难

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#include <cstdio>
#include <iostream>
using namespace std;

int main() {
    int a, b;
    cin >> a >> b;
    int c = (a + (b % 7));
    cout <<  (c > 7 ? c % 7 : c);
    return 0;
}

1020 helloworld

如果用char数组，用范围遍历会多出一个以\0字符结尾的输出，

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#include <cstdio>
#include <iostream>
#include <cstring>
using namespace std;

int main() {
    string a = "hello world";
    for (auto i : a) printf("%c", i + 1);
    return 0;
}

1021 a+b

%x输出十六进制数

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#include <cstdio>
#include <iostream>
#include <cstring>
using namespace std;

int main() {
    int a, b;
    cin >> a >> b;
    printf("%x\n", a + b);
    return 0;
}

1022 整数的个位

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#include <cstdio>
#include <iostream>
#include <cstring>
using namespace std;

int main() {
    int a;
    cin >> a;
    printf("%d\n", a % 10);
    return 0;
}

1023 整数的十位

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#include <cstdio>
#include <iostream>
#include <cstring>
using namespace std;

int main() {
    int a;
    cin >> a;
    printf("%d\n", a / 10 % 10);
    return 0;
}

1024 反向输出一个四位数

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#include <cstdio>
#include <iostream>
#include <cstring>
using namespace std;

int main() {
    int a;
    cin >> a;
    while (a) {
        cout << a % 10;
        a /= 10;
    }
    return 0;
}

1025 总成绩和平均分计算

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#include <cstdio>
#include <iostream>
#include <cstring>
using namespace std;

int main() {
    double a, b, c;
    cin >> a >> b >> c;
    double sum = a + b + c;
    printf("%.2f %.2f", sum, sum / 3);
    return 0;
}

1026 计算平均成绩

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#include <cstdio>
#include <iostream>
#include <cstring>
using namespace std;

int main() {
    int x, sum = 0;
    for (int i = 0; i < 5; i ++) {
        cin >> x;
        sum += x;
    }
    printf("%.1f", sum * 1.0 / 5);
    return 0;
}

1027 牛牛学梯形

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#include <cstdio>
#include <iostream>
#include <cstring>
using namespace std;

int main() {
    int u, d, h;
    cin >> u >> d >> h;
    printf("%.3f", (u + d) * h / 2.0);
    return 0;
}

1028 牛牛学矩形

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#include <cstdio>
#include <iostream>
#include <cstring>
using namespace std;

int main() {
    int a, b;
    cin >> a >> b;
    printf("%d\n%d", (a + b) * 2, a * b);
    return 0;
}

1029 牛牛学立体

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#include <cstdio>
#include <iostream>
#include <cstring>
using namespace std;

int main() {
    int a, b, c;
    cin >> a >> b >> c;
    printf("%d\n%d", (a * b + b * c + a * c) * 2, a * b * c);
    return 0;
}

1030 计算三角形的周长和面积

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int a, b, c;
    cin >> a >> b >> c;
    double d = a + b + c;
    double p = d / 2.0;
    double s = sqrt(p * (p - a) * (p - b) * (p - c));
    printf("circumference=%.2f area=%.2f", d, s);
    return 0;
}

1031 你能活多少秒

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    const int s = 3.156 * 1e7;
    int a;
    cin >> a;
    cout << 1LL * a * s << endl;
    return 0;
}

1032 时间转换

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int a;
    cin >> a;
    int h = a / 3600;
    int m = a % 3600 / 60;
    int s = a % 60;
    printf("%d %d %d", h, m, s);
    return 0;
}

1033 温度转换

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    double f;
    cin >> f;
    printf("%.3f", 5.0/9*(f - 32));
    return 0;
}

1034 计算机内存

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int n;
    cin >> n;
    cout << (n * 1024 * 1024 / 4) << endl;
    return 0;
}

1035 [NOIP2017]成绩

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int a, b, c;
    cin >> a >> b >> c;
    cout << (0.2 * a) + (0.3 * b) + (0.5 * c) << endl;
    return 0;
}

1036 KiKi的最高分

max

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int a, b, c;
    cin >> a >> b >> c;
    cout << max(a, max(b, c)) << endl;
    return 0;
}

1037 组队比赛

贪心

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int a, b, c, d;
    cin >> a >> b >> c >> d;
    int sum = a + b + c + d;
    int mx = max(a, max(b, max(c, d)));
    int mi =  min(a, min(b, min(c, d)));
    cout << abs((mx + mi) * 2 - sum) << endl;
    return 0;
}

1038 平方根

数据量不大，直接暴力了。这题标准做法应该用二分。

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int a;
    cin >> a;
    int ans = 1;
    while (ans * ans <= a) ans ++;
    cout << ans - 1;
    return 0;
}

1039 长方体

列方程求解

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int a, b , c;
    cin >> a >> b >> c;
    int x, y, z;
    y = sqrt(a * c / b);
    x = a / y;
    z = c / y;
    cout << (x + y + z) * 4 << endl;
    return 0;
}

1040 使徒袭来

要看清题目，求的是正实数不是正整数

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int n;
    cin >> n;
    printf("%.3f", 3 * pow(n, 1.0 / 3));
    return 0;
}

1041 白兔的分身术

思维、看题目！

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

using LL = long long;
int main() {
    LL n;
    cin >> n;
    cout << n + 1 << endl;
    return 0;
}

1042 纸牌

贪心

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int n;
    cin >> n;
    cout << (n + 1) / 2 << endl;
    return 0;
}

1043 Tobaku Mokushiroku Kaiji

贪心

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int a, b, c, d, e, f;
    cin >> a >> b >> c >> d >> e >> f;
    int ans = min(a, e) + min(b, f) + min(c, d);
    cout << ans << endl;
    return 0;
}

1044 珂朵莉的假动态仙人掌

贪心

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int n;
    cin >> n;
    int ans = 0;
    int t = 1;
    while (n >= t)
    {
        n -= t;
        t = 3 - t;
        ans ++;
    }
    cout << ans << endl;
    return 0;
}

1045 旅游观光

思维

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int n;
    cin >> n;
    cout << (n + 1) / 2  - 1 << endl;
    return 0;
}

1046 [NOIP2002]自由落体

1

1047 挂科

数学

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int n, x, y;
    cin >> n >> x >> y;
    cout << min(x, y) << " " << max(0, (x + y - n)) << endl;
    return 0;
}

1048 得不到的爱情

属实不懂了

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int n, m;
    cin >> n >> m;
    cout << 1LL * n * m - n - m << endl;
    return 0;
}

2. 选择结构习题

牛客竞赛语法入门班选择结构习题

A 比大小

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int a, b;
    cin >> a >> b;
    if (a == b) cout << '=';
    if (a > b) cout << '>';
    if (a < b) cout << '<';
    return 0;
}

B 卡拉兹函数

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int a;
    cin >> a;
    if (a & 1) cout << 3 * a + 1;
    else cout << a / 2;
    return 0;
}

C 默契

这个空格没复制到，wa了几次

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int a, b; 
    cin >> a >> b;
    if (a == b) cout << "Tacit！";
    else cout << "No Tacit!";
    return 0;
}

D 整除判断

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int a, b; 
    cin >> a >> b;
    if (a % b == 0) cout << "YES";
    else cout << "NO";
    return 0;
}

E CSimplemathproblem

题目没看清

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    long long x, y;
    cin >> x >> y;
    if (y % x == 0) cout <<x + y;
    else cout << y - x;
    return 0;
}

F 吃瓜群众

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int w;
    cin >> w;
    if (w > 2 && w % 2 == 0) cout << "YES, you can divide the watermelon into two even parts.";
    else cout << "NO, you can't divide the watermelon into two even parts.";
    return 0;
}

G jyq跳格子

思维题

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int w;
    cin >> w;
    if ((w - 1) % 2 == 0) cout << w;
    else cout << -1;
    return 0;
}

H 小名的回答

思维

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int a, b, n;
    cin >> a >> b >> n;
    if (a + b <= n && (n - a - b) % 2 == 0) cout << "YES";
    else cout << "NO";
    return 0;
}

I 牛妹数

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int n;
    cin >> n;
    if (n > 50 && n % 2 == 0) cout << "yes";
    else cout << "no";
    return 0;
}

J 判断闰年

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int n;
    cin >> n;
    if ((n % 100 != 0 && n % 4 == 0) || n % 400 == 0) cout << "yes";
    else cout << "no";
    return 0;
}

K 统计数据正负个数

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int x, a = 0, b = 0, n = 10;
    while (n --)
    {
        cin >> x;
        if (x > 0) a ++;
        else if (x < 0) b ++;
    }
    cout << "positive:" << a << endl << "negative:" << b;
    return 0;
}

L 小乐乐是否被叫家长

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int a, b, c;
    cin >> a >> b >> c;
    if (((a + b + c) / 3.0) < 60) cout << "YES";
    else cout << "NO";
    return 0;
}

M 最大最小值

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int a, b, c;
    cin >> a >> b >> c;
    int mx = max(a, max(b, c));
    int mi = min(a, min(b, c));
    cout << "The maximum number is : " << mx << endl;
    cout << "The minimum number is : " << mi << endl;
    return 0;
}

N 送分题

有1的话，就加，没有就乘。可以添加括号，意味后面两个可能先加得到的结果更大

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int get(int a, int b)
{
    return (a == 1 || b == 1) ? a + b : a * b;
}
int main() {
    int a, b, c;
    cin >> a >> b >> c; 
    if (c == 1)
        cout << get(a, get(b, c));
    else
        cout << get(get(a, b), c);
    return 0;
}

O 四季

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int ym;
    cin >> ym;
    int m = ym % 100;
    string ans;
    if (m >= 3 && m <= 5) ans = "spring";
    else if (m >= 6 && m <= 8) ans = "summer";
    else if (m >= 9 && m <= 11) ans = "autumn";
    else ans = "winter";
    cout << ans;
    return 0;
}

P B是不是太迟了

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int y, m, d;
    char c;
    cin >> y >> c >> m >> c >> d;
    if (m < 10 || (m == 10 && d < 29)) cout << "No. It's not too late.";
    else cout << "QAQ";
    return 0;
}

Q 前天是哪天

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 #include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int y, m, d;
    char c;
    cin >> y >> c >> m >> c >> d;
    d -= 2;
    if (d < 1) {
        --m;
        if (m < 1) {
            m = 12;
            --y;
        }
        if (m == 1 || m == 3 || m == 5 || m == 7 || m == 8 || m == 10 || m == 12) {
            d = 31 + d;
        }
        if (m == 4 || m == 6 || m == 9 || m == 11) {
            d = 30 + d;
        }
        if (m == 2)
        {
            if (y % 400 == 0 || (y % 4 == 0 && y % 100 != 0)) d = 29 + d;
            else d = 28 + d;
        }
    }
    printf("%d-%02d-%02d", y, m, d);
    return 0; 
}

R L1-2单位换算

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int a;
    cin >> a;
    cout << a * 12.0 *2.54 * 10;
    return 0; 
}

S 纸牌

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int n;
    cin >> n;
    cout << (n + 1) / 2 << endl;
    return 0;
}

T 排队领水

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int n, a, b;
    cin >> n >> a >> b;
    cout << min(n - a, b + 1);
    return 0;
}

U 可编程拖拉机比赛

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int n;
    cin >> n;
    int a = ceil(n * 0.1) - floor(n * 0.1);
    int b = a + ceil(n * 0.2) - floor(n * 0.2);
    int c = b + ceil(n * 0.3) - floor(n * 0.3);
    printf("%d %d %d", a, b, c);
    return 0;
}

V [NOIP2004]不高兴的津津

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main() {
    int d = 0, mx = 0;
    for (int i = 1; i <= 7; i ++)
    {
        int a, b; cin >> a >> b;
        if (a + b >= 8 && a + b > mx) {
            mx = a + b;
            d = i;
        }
    }
    cout << d;
    return 0;
}

W [NOIP2008]ISBN号码

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#include <cstdio>
#include <iostream>
#include <cstring>
#include <algorithm>
#include <cmath>
using namespace std;

int main()  {
    string s;
    cin >> s;
    int num = 0;
    int id = 1;
    for (int i = 0; i < s.size() - 1; i ++)
    {
        if (isdigit(s[i])) num += (s[i] - '0') * id++;
    }
    num %= 11;
    if ((num == 10 && s.back() == 'X') || (num == s.back() - '0'))
        cout << "Right";
    else {
        if (num == 10) s.back() = 'X';
        else s.back() = (char)(num + '0');
        cout << s;
    }
    return 0;
}

3. 循环结构习题

1001 上下金字塔

以中间最长的行，分割成上下两部分，先输出上部分，再输出最长的行，然后是下部分。

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#include <bits/stdc++.h>

using namespace std;

void p(int n)
{
    int len = n * 2 - 1;
    for (int i = 1; i < n; i ++)
    {
        int sum = 2 * i - 1;
        for (int j = 0; j < (len - sum) / 2; j ++) printf(" ");
        for (int j = 0; j < sum; j ++) printf("*"); 
        for (int j = 0; j < (len - sum) / 2; j ++) printf(" "); puts("");
    } 
    for (int i = 0; i < len; i ++) printf("*"); puts("");
    for (int i = n - 1; i > 0; i --)
    {
        int sum = 2 * i - 1;
        for (int j = 0; j < (len - sum) / 2; j ++) printf(" ");
        for (int j = 0; j < sum; j ++) printf("*"); 
        for (int j = 0; j < (len - sum) / 2; j ++) printf(" "); puts("");
    } 
}
int main()
{
    int n;
    while (cin >> n)
    {
        p(n);
    }
    return 0;
}

1002 数字三角形

模拟

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#include <iostream>

using namespace std;

int main()
{
    int n;
    cin >> n;
    int t = 1;
    for (int i = 1; i <= n; i ++)
    {
        for (int j = 0; j < i; j ++)
        {
            printf("%4d", t ++);
        }
        puts("");
    }
    return 0;
}

1003 字符金字塔

每行分四个部分考虑

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#include <iostream>

using namespace std;

int main()
{
    char c;
    cin >> c;
    for (int i = 'A'; i <= c; i ++)
    {
        for (int j = 0; j < c - i; j ++) printf(" ");
        for (int j = 'A'; j < i; j ++) printf("%c", j);
        printf("%c", i);
        for (int j = i - 1; j >= 'A'; j --) printf("%c", j);
        puts("");
    }
    return 0;
}

1004 涂小天与他的画

麻了

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#include <iostream>
#include <cstdio>
using namespace std;

int main()
{
    int T;
    cin >> T;
    while (T --)
    {
        int n;
        cin >> n; 
        
        int len = 2 * n;
//		前  
        for (int i = 1; i <= n / 2; i ++)
        {
            for (int j = i; j <= n / 2; j ++) printf(" ");
            for (int j = 1; j <= 2 * i - 1; j ++) printf("*");
            puts("");
        }
//      中 
        for (int i = 0; i < n; i ++) printf("*"); puts("");
//      后 
        for (int i = 1; i <= n / 2; i ++)
        {
            for (int j = 1; j <= i; j ++) printf(" ");
            for (int j = 1; j <= n - 2 * i; j ++) printf("*");
            puts("");
        }
    }
    return 0;
}

1005 箭形图案

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#include <bits/stdc++.h>
using namespace std;

int main()
{
    int n;
    while (cin >> n)
    {
        for (int i = 1; i <= n; i ++)
        {
            for (int j = 1; j <= (n - i + 1) * 2; j ++) cout << ' ';
            for (int j = 1; j <= i; j ++) cout << '*';
            puts("");
        }
        for (int i = 0; i <= n; i ++) cout << '*'; puts("");
        for (int i = n; i > 0; i --)
        {
            for (int j = 1; j <= (n - i + 1) * 2; j ++) cout << ' ';
            for (int j = 1; j <= i; j ++) cout << '*';
            puts("");
        }
    }
    return 0;
}

1006 牛牛学数列

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#include <bits/stdc++.h>
using namespace std;

int main()
{
    int n;
    cin >> n;
    int ans;
    for (int i = 1; i <= n; i ++)
        ans += (i & 1 ? i : -i);
    cout << ans;
    return 0;
}

1007 牛牛学数列2

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#include <bits/stdc++.h>
using namespace std;

int main()
{
    int n;
    cin >> n;
    double ans;
    for (int i = 1; i <= n; i ++)
        ans += 1.0 / i;
    printf("%.6f", ans);
    return 0;
}

1008 牛牛学数列3

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#include <bits/stdc++.h>
using namespace std;

int main()
{
    int n;
    cin >> n;
    double ans;
    int t = 0;
    for (int i = 1; i <= n; i ++)
    {
        t += (i & 1 ? 2 * i - 1 : -(2 * i - 1));
        ans += 1.0 / t;
    }
    printf("%.3f", ans);
    return 0;
}

1009 牛牛学数列4

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#include <bits/stdc++.h>
using namespace std;

int main()
{
    int n;
    cin >> n;
    long ans = 0;
    int sum = 0;
    for (int i = 1; i <= n; i ++)
    {
        sum += i;
        ans += sum;
    }
    cout << ans;
    return 0;
}

1010 牛牛学数列5

斐波那契数列

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#include <bits/stdc++.h>
using namespace std;

int main()
{
    int n;
    cin >> n;
    int a = 0, b = 1, c;
    while (--n)
    {
        c = a + b;
        a = b;
        b = c;
    }
    cout << b;
    return 0;
}

1011 牛牛学数列6

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#include <bits/stdc++.h>
using namespace std;

int main()
{
    int n;
    cin >> n;
    int a = 0, b = 1, c = 1, d;
    while (--n)
    {
        d = a + 2 * b + c;
        a = b;
        b = c;
        c = d;
    }
    cout << a;
    return 0;
}

1012 A+B

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#include <bits/stdc++.h>
using namespace std;

int main()
{
    long long a, b;
    while (cin >> a >> b)
    {
        cout << a + b << endl;
    }
    return 0;
}

1013 多组输入a+b

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#include <bits/stdc++.h>
using namespace std;

int main()
{
    long long a, b;
    while (cin >> a >> b)
    {
        cout << a + b << endl;
    }
    return 0;
}

1014 多组输入a+b II

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#include <bits/stdc++.h>
using namespace std;

int main()
{
    int n;
    cin >> n;
    long long a, b;
    while (n -- && cin >> a >> b)
    {
        cout << a + b << endl;
    }
    return 0;
}

1015 多组数据a+b III

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#include <bits/stdc++.h>
using namespace std;

int main()
{
    long long a, b;
    while (cin >> a >> b)
    {
        if (!a && !b) break;
        cout << a + b << endl;
    }
    return 0;
}

1016 [NOIP2018]标题统计

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#include <bits/stdc++.h>
using namespace std;

int main()
{
    string a;
    getline(cin, a);
    int ans = 0;
    for (auto c : a)
    {
        if(isdigit(c) || isalpha(c)) ans ++;
    }
    cout << ans;
    return 0;
}

1017 栗酱数数

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#include <bits/stdc++.h>
using namespace std;
bool not4(int n)
{
    while (n) {
        if (n % 10 == 4) return false;
        n /= 10;
    }
    return true;
}
int main()
{
    int n;
    cin >> n;
    for (int i = 1; i <= n; i++)
        if (i % 4 != 0 && not4(i))
            cout << i << endl;
    return 0;
}

1018 有趣的二进制

1

1019 [NOIP2006]数列

1

1020 只能吃土豆的牛牛

1

1021 [NOIP2015]金币

1

1022 托米历险记

1

1023 绩点

1

1024 买铅笔

1

1025 整数个数

1

1026 栗酱的文明2

1

1027 黑大火与他的猫

1

1028 [NOIP2000]进制转换

1

1029 素数判断

1

1030 Game

1

1031 [NOIP1999]Cantor表

1

1032 最大的差

1

1033 成绩统计

1

1034 糖果俱乐部

1

1035 数字计数

1

1036 热杆上的蚂蚁

1

1037 焦虑的蚂蚁

1

1038 拯救小a

1

1040 YoungManDon’tSayFive

1

1041 魔法数字变换

1

1042 [NOIP2005]陶陶摘苹果

1

1043 [NOIP2004]津津的储蓄计划

1

1044 [NOIP2002]级数求和

1

1045 cayun日常之赏月

1

1046 鹏

1

1047 D博弈与核心能源动力

1

1048 好数

1

1049 3和5和7

1

1050 回文对称数

1

1051 数位之和

1

1047 D博弈与核心能源动力

1

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