51nod 1137 矩阵乘法

#include <vector>
#include <cstring>
#include <malloc.h>
#include <cstdio>
#include <algorithm>

using namespace std ;

int a[1005][1005] ;
int b[1005][1005] ;
int ans[1005][1005] ;

int (){
    int n ;
    while ( cin >> n ){
        for ( int i = 0 ; i < n ; i ++ ){
            for ( int j = 0 ; j < n ; j ++ ){
                cin >> a[i][j] ;
            }
        }
        for ( int i = 0 ; i < n ; i ++ ){
            for ( int j = 0 ; j < n ; j ++ ){
                cin >> b[i][j] ;
            }
        }
        for ( int i = 0 ; i < n ; i ++ ){
            for ( int j = 0 ; j < n ; j ++ ){
                for ( int k = 0 ; k < n ; k ++ ){
                    ans[i][j] += a[i][k] * b[k][j] ;
                }
            }
        }
        for ( int i = 0 ; i < n ; i ++ ){
            for ( int j = 0 ; j < n ; j ++ ){
                j == 0 || cout << " " ;
                cout << ans[i][j] ;
            }
            cout << endl ;
        }
    }
    return 0 ;
}