305.網絡的核

#include <bits/stdc++.h>
using namespace std;
const int maxn = 110;
const int inf = 0x3f3f3f3f;
int mp[maxn][maxn];
int main()
{
	int t;
	scanf("%d", &t);
	while(t--)
	{
		int n, m;
		scanf("%d%d", &n, &m);
		
		for(int i = 0; i < n; i++)
		{
			for(int j = 0; j < n; j++)
				{
					if(i == j)
						mp[i][j] = 0;
					else
						mp[i][j] = inf;
				}
		}
		int a, b;
		for(int i = 0; i < m; i++)
		{
			scanf("%d%d", &a, &b);
			mp[a-1][b-1] = mp[b-1][a-1] = 1;
		}
		
		for(int k = 0; k < n; k++)
		{
			for(int i = 0; i < n; i++)
			{
				for(int j = 0; j < n; j++)
				{
					if(mp[i][j] > mp[i][k] + mp[k][j])
					{
						mp[i][j] = mp[i][k] + mp[k][j];
					}
				}
			}
		}
		
		for(int i = 0; i < n; i++)
		{
			for(int j = 0; j < n; j++)
				{
					if(mp[i][j] == inf)
						mp[i][j] = n;
				}
		}
		
		int ans = inf;
		int pos = 0;
		
		for(int i = 0; i < n; i++)
		{
			int tmp = 0;
			for(int j = 0; j < n; j++)
			{
				tmp += mp[i][j];
			}
			if(ans > tmp)
			{
				ans = tmp;
				pos = i;
			}
		}
		cout<<pos+1<<endl;
		
	}
	return 0;
} 
/*
2
3 3
1 2
1 3
2 3
4 2
1 2
2 3



*/