hdu 2544 最短路(dijkstra邻接矩阵)

/*
  Name: 最短路(dijkstra邻接矩阵) 
  Copyright: 
  Author: Try_86
  Date: 12/04/12 18:09
  Description: 
*/


#include <cstdio>
#include <cstring>
#include <iostream>

using namespace std;

const int N = 105;  
const int MAX = 1000000000;//定义无穷大 

bool vis[N];
int map[N][N], dis[N];

void init(int vs) {//初始化 
    for (int i=1; i<vs; ++i) {
        map[i][i] = 0;
        for (int j=i+1; j<=vs; ++j) map[i][j] = map[j][i] = MAX;
    }
    return ;
}

void dijkstra(int vs, int s) {
    memset(vis, false, sizeof(vis));
    int pos = s;
    vis[pos] = true;
    for (int i=1; i<=vs; ++i) dis[i] = map[pos][i];
    dis[pos] = 0;
    int minLen;
    for (int i=1; i<vs; ++i) {
        minLen = MAX;
        for (int j=1; j<=vs; ++j) {
            if (!vis[j] && minLen>dis[j]) minLen = dis[j], pos = j;
        }
        vis[pos] = true;
        for (int j=1; j<=vs; ++j) {
            int len = dis[pos]+map[pos][j];//松弛操作 
            if (!vis[j] && dis[j]>len) dis[j] = len;
        }
    }
    return ;
}

int main() {
    int n, m;
    while (scanf("%d%d", &n, &m), n+m) {
        init(n);
        int u, v, w;
        for (int i=0; i<m; ++i) {
            scanf ("%d%d%d", &u, &v, &w);
            if (map[u][v] > w) map[v][u] = map[u][v] = w;//去重边，并选择最短的一条 
        }
        dijkstra(n, 1);
        printf ("%d\n", dis[n]);
    }
    return 0;
}