Largest Number

描述

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.

分析

这题可以先把每个整数变成字符串，得到一个字符串数组，然后把这个数组按特定规则排个序，顺序输出即可。

代码

  1. // Largest Number
  2. // Time Complexity: O(n), Space Complexity: O(n)
  3. public class Solution {
  4.     public String largestNumber(int[] nums) {
  5.         final String[] strings = new String[nums.length];
  6.         for (int i = 0; i < nums.length; ++i) {
  7.             strings[i] = String.valueOf(nums[i]);
  8.         }
  9.         Arrays.sort(strings, (String s1, String s2) -> {
  10.             String leftRight = s1 + s2;
  11.             String rightLeft = s2 + s1;
  12.             return -leftRight.compareTo(rightLeft);
  13.         });
  16.         StringBuilder sb = new StringBuilder();
  17.         for (final String s : strings) {
  18.             sb.append(s);
  19.         }
  21.         while(sb.charAt(0)=='0' && sb.length()>1){
  22.             sb.deleteCharAt(0);
  23.         }
  25.         return sb.toString();
  26.     }
  27. }

原文: https://soulmachine.gitbooks.io/algorithm-essentials/content/java/sorting/other/largest-number.html