hdu 1869 floyd

认识的人之间建立一条权值为1的边，然后求出各对顶点之间的最短路判断是否有长度大于7的。

#include <algorithm>
#include <iostream>
#include <cstring>
#include <cstdio>
using namespace std;

const int INF = 999999;
const int N = 100;
int g[N][N];
int n, m;

void init()
{
    for ( int i = 0; i < n; i++ )
    {
        for ( int j = 0; j < n; j++ )
        {
            g[i][j] = INF;
        }
    }
}

void floyd()
{
    for ( int k = 0; k < n; k++ )
    {
        for ( int i = 0; i < n; i++ )
        {
            for ( int j = 0; j < n; j++ )
            {
                if ( g[i][k] + g[k][j] < g[i][j] )
                {
                    g[i][j] = g[i][k] + g[k][j];
                }
            }
        }
    }
}

void judge()
{
    for ( int i = 0; i < n; i++ )
    {
        for ( int j = 0; j < n; j++ )
        {
            if ( i == j ) continue;
            if ( g[i][j] > 7 )
            {
                printf("No
");
                return ;
            }
        }
    }
    printf("Yes
");
}

int main ()
{
    while ( scanf("%d%d", &n, &m) != EOF )
    {
        init();
        while ( m-- )
        {
            int a, b;
            scanf("%d%d", &a, &b);
            g[a][b] = g[b][a] = 1;
        }
        floyd();
        judge();
    }
    return 0;
}