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Given a list of non negative integers, arrange them such that they form the largest number.
For example, given [3, 30, 34, 5, 9], the largest formed number is 9534330.
Note: The result may be very large, so you need to return a string instead of an integer.
注意：
1. 这里的比较方法是如果 a + b > b + a 则 a > b ， 即 比较 30 和 34 , 因为 3034 < 3430， 所以34 比 30 大。
2. priorityqueue 默认是从小到大输出的。 所以在comparator里面 大的return -1！
1 public class Solution { 2 3 public String largestNumber(int[] num) { 4 PriorityQueue<Integer> pq = new PriorityQueue<Integer>( 5 new Comparator<Integer>() { 6 public int compare(Integer a, Integer b){ 7 StringBuilder sb = new StringBuilder(); 8 sb.append(a); 9 sb.append(b); 10 int first = Integer.valueOf(sb.toString()); 11 sb = new StringBuilder(); 12 sb.append(b); 13 sb.append(a); 14 int second = Integer.valueOf(sb.toString()); 15 if(first > second) return -1; 16 else if(first == second) return 0; 17 else return 1; 18 } 19 } 20 ); 21 StringBuilder sb = new StringBuilder(); 22 for(int i = 0; i < num.length; i ++){ 23 pq.add(num[i]); 24 } 25 for(int i = 0; i < num.length; i ++){ 26 sb.append(pq.poll()); 27 } 28 return sb.charAt(0) == ‘0‘ ? new String("0") : sb.toString(); 29 } 30 }
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原文地址：http://www.cnblogs.com/reynold-lei/p/4226810.html
