2015年海淀区信息学竞赛小学组详细答案

#include <iostream>using namespace std;int main(){    int n;    cin >> n;    int cnt1 = 0, cnt2 = 0, cnt3 = 0, cnt4 = 0;    int a[n];    for(int i = 0; i < n; i++)    {        cin >> a[i];        if(a[i] >= 90 && a[i] <= 100)        {            cnt1++;        }        else if(a[i] >= 80 && a[i] <= 89)        {            cnt2++;        }        else if(a[i] >= 60 && a[i] <= 79)        {            cnt3++;        }        else        {            cnt4++;        }    }    cout << "You " << cnt1 << endl;    cout << "Liang " << cnt2 << endl;    cout << "Zhong " << cnt3 << endl;    cout << "Cha " << cnt4 << endl;    return 0;}

#include <iostream>using namespace std;int main(){    int n;    cin >> n;    for(int i = 1; i <= 2 * n - 1; i++)    {        int j = (i > n) ? 2 * n - i : i;        for(int k = 1; k < j; k++)        {            cout << ' ';        }        char c;        for(c = 'A' + j - 1; c < 'A' + n; c++)        {            cout << c;        }        for(c = c - 2; c >= 'A' + j - 1; c--)        {            cout << c;        }        cout << endl;    }    return 0;}

#include<bits/stdc++.h>using namespace std;bool isprime(int a){    if(a == 1)    {        return false;    }    for(int i = 2; i <= sqrt(a); i++)    {        if(a % i == 0)        {            return false;        }    }    return true;}int main(){    int l, r, sum = 0;    cin >> l >> r;    for(int i = l; i <= r; i++)    {        if(isprime(i) &&            sqrt(i / 100) - (int)sqrt(i / 100) == 0 &&            sqrt(i % 100) - (int)sqrt(i % 100) == 0)        {            cout << i << endl;            sum++;        }    }    cout << sum << endl;    return 0;}