把数组排成最小数

package test;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.TreeMap;
import java.util.TreeSet;




public class Test3 {
		
	
	static void solve(String[] arr,int low, int high){
		if(low<high){
			int index = partition(arr, low, high);
			solve(arr, low, index-1);
			solve(arr, index+1,high);
		}
	}
		
	static int partition(String[] arr,int low,int high){
		String flag = arr[low];
		while(low<high){
			while(low<high && com(arr[high],flag)>-1) high--;
			arr[low] = arr[high];
			while(low<high && com(arr[low],flag)<1) low++;
			arr[high] = arr[low];			
		}		
		arr[low] = flag;
		return low;
	}
	
	static int com(String a,String b){		
		return (a+b).compareTo(b+a);				
	}
	
	public static void main(String[] args) {					
		//int[] arr = new int[]{3,32,321,1};
		String[] arr = new String[]{"3","32","321","1"};
		solve(arr, 0, arr.length-1);
		System.out.println(Arrays.toString(arr));
	}
}

思路：改变快速排序的比较规则，也就是比较a,b大小，变成ab和ba的大小即可