hdu 2544 最短路

最短路

Time Limit: 5000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others) Total Submission(s): 24512    Accepted Submission(s): 10549

Problem Description

在每年的校赛里，所有进入决赛的同学都会获得一件很漂亮的t-shirt。但是每当我们的工作人员把上百件的衣服从商店运回到赛场的时候，却是非常累的！所以现在他们想要寻找最短的从商店到赛场的路线，你可以帮助他们吗？

 

Input

输入包括多组数据。每组数据第一行是两个整数N、M（N<=100，M<=10000），N表示成都的大街上有几个路口，标号为1的路口是商店所在地，标号为N的路口是赛场所在地，M则表示在成都有几条路。N=M=0表示输入结束。接下来M行，每行包括3个整数A，B，C（1<=A,B<=N,1<=C<=1000）,表示在路口A与路口B之间有一条路，我们的工作人员需要C分钟的时间走过这条路。 输入保证至少存在1条商店到赛场的路线。

 

Output

对于每组输入，输出一行，表示工作人员从商店走到赛场的最短时间

 

Sample Input

2 1 1 2 3 3 3 1 2 5 2 3 5 3 1 2 0 0

 

Sample Output

3 2

 

Source

UESTC 6th Programming Contest Online

 

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闲的蛋疼，

#include<cstdio>
#include<iostream>
#include<algorithm>
#include<queue>

using namespace std;

#define MAXN 100 + 5
#define MAXM 20000 + 5

int n, m;
int d[MAXN], h[MAXN], cnt;

struct node{
    int u, w;
    bool operator < (const node &rhs)const{
        return w > rhs.w;
    }
};

struct edge{
    int v, w, nxt;
}e[MAXM];


void add(int u, int v, int w){
    e[cnt]=(edge){v, w, h[u]};
    h[u]=cnt++;

    e[cnt]=(edge){u, w, h[v]};
    h[v]=cnt++;
}

#define INF (1<<30)
bool done[MAXN];

int dijkstra(int s, int t){
    fill_n(d+1, n, INF);        d[1]=0;
    fill_n(done+1, n, false);
    priority_queue<node> q;
    q.push((node){1, d[1]});
    while(!q.empty()){
        node tu = q.top();   q.pop();
        int u = tu.u, i;
        if(done[u]) continue;   done[u]=true;
        if(u==t) return d[t];
        for(i=h[u]; i!=-1; i=e[i].nxt){
            int v = e[i].v, w = e[i].w;
            if(d[v] > d[u] + w){
                d[v] = d[u] + w;
                q.push((node){v, d[v]});
            }
        }
    }
    return d[t];
}

int main(){
    while(scanf(" %d %d", &n, &m)==2 && (n|m)){
        int i, j;
        cnt = 0;        fill_n(h+1, n, -1);
        for(i=0; i<m; i++){
            int u, v, w;
            scanf("%d %d %d", &u, &v, &w);
            add(u, v, w);
        }
        printf("%d
", dijkstra(1, n));
    }
    return 0;
}

java :

import java.awt.Point;
import java.io.File;
import java.io.FileNotFoundException;
import java.util.Comparator;
import java.util.PriorityQueue;
import java.util.Scanner;

class MyComp implements Comparator<Point>{
	@Override
	public int compare(Point o1, Point o2) {
		// TODO Auto-generated method stub
		if(o1.y==o2.y) return 0;
		return o1.y<o2.y ? -1 : 1;
	}
}

class Dijkstra{
	static final int MAXN=111,
						MAXM=22222;
	static final int INF = 10000000;
	
	final int s, t;
	boolean[] vis = new boolean[MAXN];
	static int[] dis = new int[MAXN];
	static int counter=0;
	int[] w = new int[MAXM],
		  next = new int[MAXM],
		  to = new int[MAXM];
	int[] h = new int[MAXN];
	static PriorityQueue<Point> q=new PriorityQueue<Point>(10,
			new MyComp());
	
	public Dijkstra(int s, int t){
		this.s=s; this.t=t;
		counter=0;
		for(int i=1; i<=t; i++) h[i]=-1;
	}
	
	private void ini(){
		for(int i=s; i<=t; i++){
			dis[i]=INF;	vis[i]=false;
		}
		q.clear();		dis[s]=0;
	}
	
	public void add(int u, int v, int _w){
		w[counter]=_w;	next[counter]=h[u];		
		to[counter]=v;	h[u]=counter++;
		w[counter]=_w; 	next[counter]=h[v];		
		to[counter]=u;	h[v]=counter++;
	}
	
	public int run(){
		ini();		q.add(new Point(s,0));
		while(!q.isEmpty()){
			Point np = new Point(q.poll());
			if(np.x == t) return dis[t];
			if(vis[np.x]) continue;	vis[np.x]=true;
			for(int i=h[np.x]; i!=-1; i=next[i]){
				int v = to[i], tw = w[i];
				if(dis[np.x]+tw<dis[v]){
					dis[v] = dis[np.x] + tw;
					q.add(new Point(v,dis[v]));
				}
			}
		}
		return dis[t];
	}
}

public class Main {
	public static void main(String[] args){
		// TODO Auto-generated method stub
//		File f = new File("F:\pro\javaPro\hdu\hdu2544");
		Scanner sc = new Scanner(System.in);
		while(sc.hasNext()){
			int n = sc.nextInt(), m=sc.nextInt();
			if(n==0 && m==0) break;
			Dijkstra dij = new Dijkstra(1, n);
			for(int i=0; i<m; i++)
				dij.add(sc.nextInt(), sc.nextInt(), sc.nextInt());
			System.out.println(dij.run());
		}
	}
}