add POJ 3268 for Java

Author: nnks1010

Java/POJ/3268/Main.java

@@ -0,0 +1,71 @@
+import java.util.LinkedList;
+import java.util.PriorityQueue;
+import java.util.Scanner;
+
+public class Main {
+	final int INF = Integer.MAX_VALUE / 3;
+	class Edge {
+		int b, t;
+		Edge(int to, int cost) {
+			this.b = to; this.t = cost;
+		}
+	}
+	class Pair implements Comparable<Pair> {
+		int f, s;
+		Pair(int cost, int to) {
+			this.f = cost; this.s = to;
+		}
+		public int compareTo(Pair p) {
+			return this.f - p.f;
+		}
+	}
+	class Graph {
+		LinkedList<Edge> edges = new LinkedList<Edge>();
+	}
+	void run() {
+		Scanner scan = new Scanner(System.in);
+		int n = scan.nextInt();
+		int m = scan.nextInt();
+		int x = scan.nextInt();
+		Graph[] g = new Graph[n + 1];
+		for (int i = 0; i <= n; i++)
+			g[i] = new Graph();
+		for (int i = 0; i < m; i++) {
+			int a = scan.nextInt();
+			int b = scan.nextInt();
+			int t = scan.nextInt();
+			g[a].edges.add(new Edge(b, t));
+		}
+		int[][] d = new int[n+1][n+1];
+		
+		PriorityQueue<Pair> que = new PriorityQueue<Pair>();
+
+		for (int t = 1; t <= n; t++) {
+			for (int i = 0; i <= n; i++)
+				d[t][i] = INF;
+			que.clear();
+			d[t][t] = 0;
+			que.add(new Pair(0, t));
+		
+			while(!que.isEmpty()) {
+				Pair p = que.poll();
+				int v = p.s;
+				if (d[t][v] < p.f) continue;
+				for (int i = 0; i < g[v].edges.size(); i++) {
+					Edge e = g[v].edges.get(i);
+					if (d[t][e.b] > d[t][v] + e.t) {
+						d[t][e.b] = d[t][v] + e.t;
+						que.add(new Pair(d[t][e.b], e.b));
+					}
+				}
+			}
+		}
+		int ans = 0;
+		for (int i = 1; i <= n; i++)
+			ans = Math.max(ans, d[i][x] + d[x][i]);
+		System.out.println(ans);
+	}
+	public static void main(String[] args) {
+		new Main().run();
+	}
+}