HDOJ——1874 畅通工程续(Dijkstra)

#include<iostream>
#include<stdio.h>
#include<stdlib.h>
using namespace std;
#define maxdis 999999

int town[305][305];
int dis[305];//目前得到的最小距离 

int final[305];

void dijkstra(int s,int t,int N){
	dis[s]=0;
	for(int times=1;times<=N;++times){
		int mint=maxdis;
		int v;
		for(int i=0;i<N;++i){
			if(!final[i]){
				if(dis[i]<mint){
					mint=dis[i];
					v=i;
				}
			}
		}
		final[v]=true;
		for(int i=0;i<N;++i){
			if(town[v][i]<maxdis){
				if((dis[v]+town[v][i])<dis[i])dis[i]=dis[v]+town[v][i];
			}
		}
	}//进行N次循环 
}

int main(){
	int N,M;
	while(scanf("%d",&N)!=EOF){
		for(int i=0;i<N;++i){
			final[i]=false;
		}
		for(int i=0;i<N;++i){
			for(int j=0;j<N;++j){
				town[i][j]=maxdis;
				town[j][i]=maxdis;
			}
		}
		for(int i=0;i<N;++i){
			dis[i]=maxdis;
		}
		scanf("%d",&M);//M条路 
		for(int i=1;i<=M;++i){
			int x,y,z;
			scanf("%d%d%d",&x,&y,&z);
			if(x==y){i--;continue;}
			if(z<town[x][y])
			{town[x][y]=z;
			town[y][x]=z;}
		}
		int s,t;
		scanf("%d%d",&s,&t);
		dijkstra(s,t,N);
		if(dis[t]>10000){cout<<-1<<endl;continue;}
		cout<<dis[t]<<endl;
	}
	return 0;
}