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【题目】
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】
1.设置一个比较器Comparator，比较两个String按不同方式拼接后的数字的大小（如String a和b，parseLong(a+b)和parseLong(b+a)）
2.考虑int的范围，当两个数字拼接后可能会超出int的范围，采用Long来拼接两个int
【算法实现】
public class Solution { public String largestNumber(int[] nums) { int len = nums.length; if(len<1) return ""; String[] str = new String[len]; for(int i=0; i<len; i++) { str[i] = String.valueOf(nums[i]); } Arrays.sort(str,new Cmp()); StringBuffer res = new StringBuffer(); for(int i=0; i<len; i++) { res.append(str[i]); } String r = res.toString(); int i = 0; while(i<len && r.charAt(i)==‘0‘) { i++; } if(i==len) return "0"; return res.toString(); } class Cmp implements Comparator<String> { public int compare(String s1, String s2) { String a = s1.concat(s2); String b = s2.concat(s1); int res; if((Long.parseLong(b)-Long.parseLong(a))>0) { res = 1; }else if((Long.parseLong(b)-Long.parseLong(a))<0) { res = -1; }else { res = 0; } return res; } } }
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原文地址：http://www.cnblogs.com/hwu2014/p/4512744.html
