1869六度分离

实在是太粗心了，floyd算法中把k打成了i，找了20分钟才找到错.... 题目不难，最多用6个人就能联系在一起，等价于任意2点的距离不超过7

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

#ifndef ONLINE_JUDGE
#include <fstream>
ifstream fin("test.txt");
#define cin fin
#endif
int graph[110][110],n,m;
const int INF = 1000000;
void floyd()
{

    int i,j,k;
    for(k = 0; k < n; ++k)
    for(i = 0; i < n; ++i)
    for(j = 0; j < n; ++j)
    graph[i][j] = min(graph[i][j],graph[i][k]+graph[k][j]);    
}
bool judge()
{
    for(int i = 0; i < n; ++i)
    for(int j = i + 1; j < n; ++j)
    if(graph[i][j] > 7)
    return 0;
    return 1;
}
int main()
{
    ios::sync_with_stdio(false);
    int a,b;
    while(cin >> n >> m)
    {
        for(int i = 0; i < n; ++i)
        for(int j = 0; j < n; ++j)
        if(i == j)
        graph[i][j] = 0;
        else
        graph[i][j] = INF;
        while(m--)
        {
            cin >> a >> b;
            graph[a][b] = graph[b][a] = 1;
        }
        floyd();
        if(judge())
        cout << "Yes" << endl;
        else
        cout << "No" << endl;
    }
    return 0;
}