稠密图用朴素Dijkstra算法，用链式前向星存储图

#include<bits/stdc++.h>
using namespace std;

const int N = 110;   
int g[N][N];
int dist[N];
bool st[N];
int n, m;

int dijkstra()
{
	 for(int i = 2;  i <= n; i ++)
        dist[i] = INT_MAX / 2;
    dist[1] = 0;
	
	for(int i = 0; i < n; i ++)
	{
		int t = -1; //表示还没有确定 
		//找还没有被确定的最短路 
		for(int j = 1; j <= n; j ++)
			if(!st[j] &&(t == -1 || dist[t] > dist[j]))
				t = j;
				
		if(t == n) break; 
		 
		st[t] =  true;
		for(int j = 1; j <= n; j ++)
			dist[j] = min(dist[j],  dist[t] + g[t][j]);
	} 
	if(dist[n] == INT_MAX / 2) return -1;
	return dist[n];
}

int main()
{
	while(cin >> n >> m)
	{
		if(!n && !m) break;
		memset(st, 0, sizeof st);
		for(int i = 1; i <= n; i ++)
			for(int j = 1; j <= n; j ++)
				g[i][j] = INT_MAX / 2;
		
		while(m --)
		{
			int a, b, w;
			cin >> a >> b >> w;
			g[a][b] = g[b][a] = min(g[a][b]...