HDU-1869六度分离

#include <iostream>
#include <cstring>
#include <cstdio>
#define maxn 107
#define INF 65535
#define min(a,b) (a)<(b)?(a):(b)
using namespace std;

int map[maxn][maxn];

void floyd(int n)
{
    for(int k = 0;k < n;k++)
        for(int i = 0;i < n;i++)
            for(int j = 0;j < n;j++)
                map[i][j] = min(map[i][j],map[i][k]+map[k][j]);
}

int main()
{
    int n,m;
    while(cin>>n>>m)
    {
        for(int i = 0;i < n;i++)
            for(int j = 0;j < n;j++)
                map[i][j] = i==j?0:INF;
        int t1,t2;
        for(int i = 0;i < m;i++)
        {
            cin>>t1>>t2;
            map[t1][t2] = map[t2][t1] = 1;
        }
        floyd(n);
        int flag = 1;
        for(int i = 1;i < n;i++)
            for(int j = 1;j < n;j++)
                if(map[i][j]>7) {
                    flag = 0;
                    break;
                }
        if(flag) cout<<"Yes"<<endl;
        else cout<<"No"<<endl;
        
    }
    return 0;
}