class Solution {
    public String minNumber(int[] nums) {
        int[] number = nums;
        if (number == null || number.length == 0) {
            return new String();
        }
        String[] strNumber = new String[number.length];
        for (int i=0; i<number.length; i++) {
            strNumber[i] = String.valueOf(number[i]);
        }
        // 快排
        quickSort(strNumber, 0, strNumber.length-1);
        // 结果转换
        StringBuilder res = new StringBuilder();
        for (String str : strNumber) {
            res.append(str);
        }
        return res.toString();
    }

    void quickSort(String[] strNumber, int start, int end)  {
        if (start >= end ) return;
        int index = partition(strNumber, start, end);
        if (index > start) {
            quickSort(strNumber, start, index-1);
        }
        if (index < end) {
            quickSort(strNumber, index+1, end);
        }
    }

    int partition(String[] strNumber, int start, int end) {

        int left = start;
        int right = end;
        String temp = strNumber[left];
        while (left < right) {
            while (left < right && ((strNumber[right]+strNumber[left]).compareTo(strNumber[left]+strNumber[right]))>=0) {
                right--;
            }
            while (left < right && ((strNumber[left]+strNumber[right]).compareTo(strNumber[right]+strNumber[left]) <= 0)) {
                left++;
            }
            temp = strNumber[left];
            strNumber[left] = strNumber[right];
            strNumber[right] = temp;
        }
        strNumber[left] = temp;
       return  left;

    }
}

// 方法二
public String minNumber(int[] nums) {
		String[] strs = new String[nums.length];
   for(int i=0; i<nums.length; i++) {
     strs[i] = String.valueOf(nums[i]);
   }
  // 快排
  Arrays.sort(strs, (x, y)->(x+y).compareTo(y+x));
  StringBuilder res = new StringBuilder();
  for(String str : strs) {
    res.append(str);
  }
  return res.toString();
      
}