11/1 NOIP 模拟赛

 

　　　　　　　　11.1 NOIP 模拟赛

期望得分：50；实际得分：50；

思路：暴力枚举 + 快速幂

#include <algorithm>
#include <cstring>
#include <cstdio>
using namespace std;
typedef long long LL;
const int Mod = 1e9 + 7;

int n, m;
LL ans;

LL qpow(LL a, LL b) {
    LL res = 1;
    while (b) {
        if (b & 1) res = res * a % Mod;
        a = a * a % Mod;
        b >>= 1;
    }
    return res;
}

int main() {
    freopen("sum.in","r",stdin);
    freopen("sum.out","w",stdout);
    scanf("%d%d", &n, &m);
    ans += m;
    for (int i = 2; i <= n; ++i) {
        ans += i;
        for (int j = 2; j <= m; ++j) {
            ans = ans + qpow(i, j);
            if (ans >= Mod) ans -= Mod;
        }
    }
    printf("%lld\n", ans);
    fclose(stdin); fclose(stdout);
    return 0;
}

考场代码