学步园

</pre><pre name="code" class="cpp"><pre name="code" class="cpp">//题意：题目意思不解释了，解释了这道题就没意思，感觉不会写代码，把题目理解，也是很有帮助的
//思路：对于这钟点比较少的最短路，第一思路就是暴力，floyd。


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


#define maxf 105
#define maxn 505
#define inf 0x3f3f3f3f


int firenum, n;
int fire[maxf];
int map[maxn][maxn];
int firedist[maxn];






void slove()
{
	for (int i = 0; i < n; i++)
		firedist[i] = inf;
	for (int i = 0; i < n; i++)//着火点
		for (int j = 0; j < firenum; j++)//消防站
			firedist[i] = min(firedist[i], map[i][fire[j]]);//着火点到消防站的最小距离
	int ans, maxdist = inf;
	for (int i = 0; i < n; i++)//假设i点有消防站
	{
		int temp = 0;
		for (int j = 0; j < n; j++)
			temp = max(temp, min(firedist[j], map[i][j]));//着火点到消防站最大距离的变化
		if (temp < maxdist)
		{
			ans = i;
			maxdist = temp;
		}
	}
	printf("%d\n", ans + 1);
}


int main()
{


	scanf("%d%d", &firenum, &n);
	for (int i = 0; i < firenum; i++)
	{
		scanf("%d", &fire[i]);
		fire[i]--;
	}
	for (int i = 0; i < n; i++)
		for (int j = 0; j < n; j++)
			if (i != j)
				map[i][j] = inf;
			else
				map[i][j] = 0;
	int a, b, c;
	while (~scanf("%d%d%d", &a, &b, &c))
	{
		a--;
		b--;
		map[a][b] = map[b][a] = min(map[a][b], c);
	}




	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]);


	slove();
	return 0;
}