poj 2387 Til the Cows Come Home

#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#define Max_N 3000
#define INF 0x3f3f3f3f
#define _min(a,b) ((a)>(b)?(b):(a))
int V,E,map[Max_N][Max_N], dist[Max_N],vis[Max_N];
void dijkstra(){
	int u;
	for (u = 0; u < V; u++) dist[u] = (u == V - 1 ? 0 : INF);
	memset(vis, 0, sizeof(vis));
	for (;;){
		int v = -1;
		for (u = 0; u < V;u++)
		if (!vis[u] && (-1 == v || dist[v]>dist[u])) v = u;
		if (-1 == v) break;
		vis[v] = 1;
		for (u = 0; u < V; u++)
			dist[u] = _min(dist[u], dist[v] + map[v][u]);
	}
	printf("%d\n", dist[0]);
}
int main(){
#ifdef LOCAL
	freopen("in.txt", "r", stdin);
	freopen("out.txt", "w+", stdout);
#endif
	while (~scanf("%d %d", &E, &V)){
		int  a, b, c, k = 0, t = E;
		for (a = 0; a < V; a++){
			for (b = 0; b < V; b++) map[a][b] = INF;
		}
		while (t--){
			scanf("%d %d %d", &a, &b, &c);
			--a, --b;
			map[a][b] = map[b][a] = _min(c, map[a][b]);
		}
		dijkstra();
	}
	return 0;
}