hdu 2544【java】最短路

最短路

Time Limit: 5000/1000 MS (Java/Others)    Memory Limit: 32768/32768 K (Java/Others)
Total Submission(s): 64242    Accepted Submission(s): 28125

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 11 2 33 31 2 52 3 53 1 20 0

 

Sample Output

32

 

运用了一下索引优先队列，当然写索引优先队列会费些时间，但是只是花些时间而已

public static void main(String args[]){Main main=new Main();while(true){int end=scan.nextInt();int num=scan.nextInt();if(end==num&&num==0){break;}main.start(end ,num);}}static Scanner scan=new Scanner(System.in);public void start(int end,int num){Graph g=new Graph(end);for(int i=0;i<num;i++){int a=scan.nextInt();int b=scan.nextInt();int c=scan.nextInt();g.add(new Edge(a,b,c));}int max=100000000;MinPQ<Double> pq=new MinPQ<Double>(end);double distTo[]=new double[end+1];for(int i=0;i<distTo.length;i++){distTo[i]=max;}distTo[1]=0;pq.insert(1,distTo[1]);while(!pq.isEmpty()){int a=pq.delete();for(Edge i:g.array[a]){if(distTo[i.other(a)]>distTo[a]+i.weight){distTo[i.other(a)]=distTo[a]+i.weight;if(!pq.continues(i.other(a))) pq.charge(i.other(a), distTo[i.other(a)]);else{pq.insert(i.other(a), distTo[i.other(a)]);}}}}System.out.println((int)distTo[end]);}class MinPQ<E extends Comparable>{E pq[];//比较数int size;int positive[];int lose[];public boolean isEmpty(){return size==0;}public void charge(int i,E key){pq[i]=key;swim(lose[i]);sink(lose[i]);}public boolean continues(int i){return lose[i]==-1;}public MinPQ(int vSize) {this.pq = (E[]) new Comparable[vSize+1];this.positive=new int[vSize+1];this.lose=new int[vSize+1];Arrays.fill(lose, -1);}public void insert(int k,E e){positive[++size]=k;pq[k]=e;lose[k]=size;swim(size);}public int delete(){int index=positive[1];exch(1,size--);sink(1);//pq[positive[size+1]]=null;//其实这地方开始就有点糊了。lose[positive[size+1]]=-1;return index;}public boolean less(int i,int j){int a=0;try{a=pq[positive[i]].compareTo(pq[positive[j]]);}catch(ArrayIndexOutOfBoundsException e){}return a==1;}public void exch(int i,int j){int d=positive[i];positive[i]=positive[j];positive[j]=d;lose[positive[i]]=i;lose[positive[j]]=j;}public void swim(int k){while(k>1){if(!less(k,k/2)) break;exch(k,k/2);k=k/2;}}public void sink(int k){while(2*k<=size){int j=2*k;if(j<size&&less(j,j+1)) j++;if(!less(j,k)) break;exch(j,k);k=j;}}}class Point implements Comparable<Point>{int v;long weight;public Point(int v, long weight) {super();this.v = v;this.weight = weight;}@Overridepublic int compareTo(Point o) {if(weight>o.weight){return 1;}else{return -1;}}@Overridepublic String toString() {return "Point [v=" + v + ", weight=" + weight + "]";}}class Graph{int vSize;ArrayList<Edge> array[];public Graph(int vSize) {super();this.vSize = vSize;array=(ArrayList<Edge>[])new ArrayList[vSize+1];for(int i=0;i<array.length;i++){array[i]=new ArrayList<Edge>();}}public void add( Edge e){array[e.v].add(e);array[e.w].add(e);}}class Edge {int w;int v;int weight;public Edge(int w, int v, int weight) {super();this.w = w;this.v = v;this.weight = weight;}public int other(int point){if(v==point) return w;else return v;}}