cf 359C

来源：互联网发布：云计算面临的安全问题编辑：程序博客网时间：2024/05/29 19:19

stl 里的map使用然后就是快速幂取余

#include <cstdio>#include <cstring>#include <algorithm>#include <cstdlib>#include <map>#define LL long long#define mod 1000000007using namespace std;LL num[100010];LL pow_mod(LL a, LL n){    if(n == 0)        return 1;    LL x = pow_mod(a, n/2);    LL ans = (LL)x*x%mod;    if(n%2) ans = ans*a%mod;    return ans;}int main(){    LL n, x, _max, sum = 0;    scanf("%I64d%I64d",&n,&x);    for(int i = 0; i < n; i++)    {        scanf("%I64d",&num[i]);        sum += num[i];    }    _max = sum;    for(int i = 0; i < n; i++)    {        num[i] = sum-num[i];        _max = min(_max, num[i]);    }    map<LL, int> g;    for(int i = 0; i < n; i++)    {        num[i] -= _max;        g[num[i]]++;    }    int r = 0;    for (int i = 0; ; i++)    {        r += g[i];        if (r % x || r == 0)            break;        r /= x;        _max++;    }    if(_max > sum)        _max = sum;    printf("%I64d\n",pow_mod(x%mod, _max));    return 0;}