HDU 1874, Dijkstra

import java.util.Arrays;import java.util.Comparator;import java.util.PriorityQueue;import java.util.Scanner;public class Main {private int n, m, s, t, cnt;private int[] head, d;private static final int MAXIMUM  = 20000000;private boolean[] done;private Edge[] e;private class Edge{int val, next, v;public Edge(int val, int next, int v){this.val = val;this.next = next;this.v = v;}}private class MyComparator<T> implements Comparator<T>{public int compare(T o1, T o2) {// TODO Auto-generated method stubPair p1 = (Pair)o1, p2 = (Pair)o2;if(p1.dis > p2.dis) return 1;return p1.dis == p2.dis ? 0 : -1;}}private class Pair{int dis,  node;public Pair(int dis, int node){this.dis=dis;this.node=node;}}private void add(int u, int v, int val){e[cnt] = new Edge(val, head[u], v);head[u] = cnt++; e[cnt] = new Edge(val, head[v], u);head[v] = cnt++;}private int dijkstra(){MyComparator<Pair> comparator = new MyComparator<Main.Pair>();PriorityQueue<Pair> q = new PriorityQueue<Pair>(10,comparator);d = new int[n + 1];Arrays.fill(d, MAXIMUM);d[s] = 0;done = new boolean[n + 1];Arrays.fill(done, false);  q.add(new Pair(0, s));while(!q.isEmpty()){Pair p = q.remove();if(p.node == t) return d[t] == MAXIMUM ? -1 : d[t];done[p.node] = true;for(int i = head[p.node]; i != -1; i = e[i].next){d[e[i].v] = Math.min(d[e[i].v], e[i].val + p.dis);if(!done[e[i].v]) q.add(new Pair(d[e[i].v], e[i].v));}}return d[t] == MAXIMUM ? -1 : d[t];}public void hdu1874(){Scanner sc = new Scanner(System.in);while(sc.hasNext()){n = sc.nextInt();m = sc.nextInt();head = new int[n+1];cnt = 0;e = new Edge[m << 2];Arrays.fill(head, -1);for(int i = 0; i < m; i++){int a = sc.nextInt(), b = sc.nextInt(), val = sc.nextInt();add(a, b, val);}s = sc.nextInt();t = sc.nextInt();System.out.println(dijkstra());}}                                                                                                                                                                                                       public static void main(String[] args) {new Main().hdu1874();}}

 

HDU 1874, Dijkstra