poj 3318 Matrix Multiplication 夜

http://poj.org/problem?id=3318

g++ re   c++ ac

受不了了

随机找了60000 个点比较的  运气好就过了

#include<iostream>
#include<cstdio>
#include<cstdlib>
#include<ctime>
#include<queue>
#include<cstring>
#include<set>
#include<cmath>
#include<algorithm>

using namespace std;

const int N=505;
int a[N][N];
int b[N][N];
int c[N][N];
int main()
{
        //freopen("data.txt","r",stdin);
        int n;
        scanf("%d",&n);
        for(int i=0;i<n;++i)
        for(int j=0;j<n;++j)
        scanf("%d",&a[i][j]);
        for(int i=0;i<n;++i)
        for(int j=0;j<n;++j)
        scanf("%d",&b[i][j]);
        for(int i=0;i<n;++i)
        for(int j=0;j<n;++j)
        scanf("%d",&c[i][j]);
        srand((unsigned int)time(NULL));
        int I=60000;
        bool flag=true;
        while(I--)
        {
            int k=rand()%n;
            int l=rand()%n;
            int temp=0;
            for(int i=0;i<n;++i)
            {
                temp+=(a[k][i]*b[i][l]);
            }
            if(temp!=c[k][l])
            {
                flag=false;
                break;
            }
        }
        if(flag==true)
        printf("YES\n");
        else
        printf("NO\n");
    return 0;
}