2019 ICPC南昌网络赛 B题

英雄灭火问题忽略了一点丫

一个超级源点的事情，需要考虑周全丫

 

 

 

 

 

 

 

 

 

 

 

2

#include<cstdio>
#include<cstring>
#include<queue>
#include<vector>
#include<iostream>
#include<algorithm>
using namespace std;
#define maxn 1010
#define INF 0x3f3f3f3f
int T, n, m, s, k, c;
struct Node {
	int p;
	int val;
	Node(int _p, int _val) :p(_p), val(_val) {}
};
vector<Node>G[maxn];
void insert(int be, int en, int len) {
	G[be].push_back(Node(en, len));
}
int dis[maxn];
int vis[maxn];
int spfa(int be) {
	queue<int>que;
	memset(vis, 0, sizeof(vis));
	memset(dis, INF, sizeof(dis));
	que.push(be);
	dis[be] = 0;
	while (!que.empty()) {
		int x = que.front();
		que.pop();
		vis[x] = 0;
		for (int i = 0; i < G[x].size(); i++) {
			int p = G[x][i].p;
			if (dis[p] > dis[x] + G[x][i].val) {
				dis[p] = dis[x] + G[x][i].val;
				if (!vis[p]) {
					que.push(p);
					vis[p] = 1;
				}
			}
		}
	}
	return 0;
}
int be, en, len;
int main() {
	scanf("%d", &T);
	while (T--) {
	
		for (int i = 0; i < maxn - 2; i++) G[i].clear();
		scanf("%d%d%d%d%d", &n, &m, &s, &k, &c);
	
		for (int i = 0; i < k; i++) {
			scanf("%d", &be);
			insert(0, be, 0);
		}
		for (int i = 0; i < m; i++) {
			scanf("%d %d %d", &be, &en, &len);
			insert(be, en, len);
			insert(en, be, len);
		}
		spfa(0);
		int ans1 = 0;
		for (int i = 1; i <= n; i++) {
			ans1 = max(ans1, dis[i]);
		}
		int ans2 = 0;
		spfa(s);
		for (int i = 1; i <= n; i++) {
			ans2 = max(ans2, dis[i]);
		}
		if (ans1*c >= ans2) printf("%d\n", ans2);
		else printf("%d\n", ans1);
	}
	return 0;
}

　　我老婆