标签：hdu2066

一个人的旅行

Time Limit: 1000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 18484    Accepted Submission(s): 6429

6 2 3
1 3 5
1 4 7
2 8 12
3 8 4
4 9 12
9 10 2
1 2
8 9 10

9

Dijkstra 31ms

//Dijkstra
#include <stdio.h>
#include <string.h>
#define INF -1
#define maxn 1002

int map[maxn][maxn];
int dist[maxn];
bool vis[maxn], exis[maxn];

int getNext(int n)
{
	int u = -1, tmp = 100000000;
	for(int i = 0; i <= n; ++i)
		if(!vis[i] && exis[i] && dist[i] != INF && dist[i] < tmp){
			tmp = dist[i]; u = i;
		}
	return u;
}

void Dijkstra(int v, int n)
{
	int i, tmp;
	dist[v] = 0;
	while(v != -1){
		for(i = 1; i <= n; ++i){
			if(map[v][i] != -1){
				tmp = dist[v] + map[v][i];
				if(dist[i] == INF || tmp < dist[i])
					dist[i] = tmp;
			}
		}
		vis[v] = 1;
		v = getNext(n);
	}
}

int main()
{
	// freopen("in.txt", "r", stdin);
	// freopen("out.txt", "w", stdout);
	int t, s, d, a, b, c, i, ans;
	while(scanf("%d%d%d", &t, &s, &d) != EOF){
		memset(map, -1, sizeof(map));
		memset(dist, -1, sizeof(dist));
		memset(vis, 0, sizeof(vis));
		memset(exis, 0, sizeof(exis));
		for(i = 0; i <= 1000; ++i) map[i][i] = 0;
		for(i = 0; i < t; ++i){
			scanf("%d%d%d", &a, &b, &c);
			if(map[a][b] == INF || c < map[a][b])
				map[a][b] = map[b][a] = c;			
			exis[a] = exis[b] = 1;
		}
		for(i = 0; i < s; ++i){
			scanf("%d", &a);
			map[0][a] = map[a][0] = 0;
		}
		Dijkstra(0, 1000);
		ans = 100000000;
		while(d--){
			scanf("%d", &a);
			if(dist[a] != INF && dist[a] < ans)
				ans = dist[a];
		}
		printf("%d\n", ans);
	}
	return 0;
}

Floyd  593ms 需要适当的剪枝，第14行若不剪会超时

//Floyd
#include <stdio.h>
#include <string.h>
#define maxn 1002
#define INF -1

int map[maxn][maxn];

void Floyd(int n)
{
	int i, j, k;
	for(k = 0; k <= n; ++k)
		for(i = 0; i <= n; ++i)
			for(j = 0; j <= n && map[i][k] != -1; ++j)
				if(map[i][k] != -1 && map[k][j] != -1 && (map[i][k] + map[k][j] < map[i][j] || map[i][j] == -1))
					map[i][j] = map[i][k] + map[k][j];
}

int main()
{
	// freopen("in.txt", "r", stdin);
	// freopen("out.txt", "w", stdout);
	int t, s, d, a, b, c, i, ans;
	while(scanf("%d%d%d", &t, &s, &d) != EOF){
		memset(map, -1, sizeof(map));
		for(i = 0; i <= 1000; ++i) map[i][i] = 0;
		for(i = 0; i < t; ++i){
			scanf("%d%d%d", &a, &b, &c);
			if(map[a][b] == -1 || c < map[a][b])
				map[a][b] = map[b][a] = c;
		}
		for(i = 0; i < s; ++i){
			scanf("%d", &a);
			map[0][a] = map[a][0] = 0;
		}
		Floyd(1000);
		ans = 100000000;
		for(i = 0; i < d; ++i){
			scanf("%d", &a);
			if(map[0][a] != -1 && map[0][a] < ans)
				ans = map[0][a];
		}
		printf("%d\n", ans);
	}
	return 0;
}

HDU2066 一个人的旅行 【Dijkstra】【Floyd】,布布扣,bubuko.com

HDU2066 一个人的旅行 【Dijkstra】【Floyd】

标签：hdu2066

原文地址：http://blog.csdn.net/chang_mu/article/details/38232855