1072 Gas Station (30 分)-优快云博客

1072 Gas Station (30 分)

思路有空更新

#include <iostream>
#include <cstring>
using namespace std;
const int inf = 0x3f3f3f3f;
int map[1050][1050], vis[1050], dis[1050];
int n, m, k, ds;
void dijkstra(int s){
	memset(vis, 0, sizeof vis);
	memset(dis, inf, sizeof dis);
	dis[s] = 0;
	for(int i = 0; i < n + m; ++i){
		int t = -1;
		for(int j = 1; j <= n + m; ++j)
			if(!vis[j] && (t == -1 || dis[j] < dis[t]))
				t = j;
		vis[t] = 1;
		for(int j = 1; j <= n + m; ++j)
			dis[j] = min(dis[j], dis[t] + map[t][j]);
	}
}
int main() {
	cin >> n >> m >> k >> ds;
	memset(map, inf, sizeof map);
	for(int i = 1; i <= n + m; ++i)
		map[i][i] = 0;
	while(k--) {
		string a, b;
		int x, y, z;
		cin >> a >> b >> z;
		if(a[0] == 'G') x = stoi(a.substr(1)) + n;
		else x = stoi(a);
		if(b[0] == 'G') y = stoi(b.substr(1)) + n;
		else y = stoi(b);
		map[x][y] = map[y][x] = z;
	}
	int index;
	double minv = inf, minD = 0;
	for(int i = n + 1; i <= n + m; ++i){
		dijkstra(i);
		int mind = inf, f = 1;
		double sum = 0;
		for(int j = 1; j <= n; ++j){
			if(dis[j] > ds){
				f = 0;break;
			}
			mind = min(mind, dis[j]);
			sum += dis[j];
		}
		if(f == 0) continue;
		if(mind > minD){
			minD = mind;
			minv = sum / n;
			index = i;
		}
		else if(mind == minD && sum / n < minv){
			minv = sum / n;
			index = i;
		}
	}
	if(minv == inf)
		cout << "No Solution";
	else
		printf("G%d\n%.1lf %.1lf", index - n, minD, minv + 1e-6);
}