1.题目描述

912. 排序数组

给定一个整数数组 nums，将该数组升序排列。

示例 1：

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输入：[5,2,3,1]
输出：[1,2,3,5]

示例 2：

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输入：[5,1,1,2,0,0]
输出：[0,0,1,1,2,5]

提示：

  • 1 <= A.length <= 10000
  • -50000 <= A[i] <= 50000

2.代码实现

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class Solution {
    public static List<Integer> sortArray(int[] nums) {
        int[] temp = new int[nums.length];

        sort(nums, 0, nums.length-1, temp);

        List<Integer> list = new ArrayList<>();
        for (int i = 0; i < nums.length; i++) {
            list.add(nums[i]);
        }
        
        return list;
    }

    public static void sort(int[] nums, int left, int right, int[] temp){
        if (left < right){
            int mid = (left+right) / 2;

            sort(nums, left, mid, temp);
            sort(nums, mid+1, right, temp);

            merge(nums, left, right, mid, temp);
        }
    }

    public static void merge(int[] nums, int left, int right, int mid, int[] temp){
        int i = left;
        int j = mid+1;
        int index = 0;

        while(i <= mid && j <= right){
            if(nums[i] > nums[j]){
                temp[index++] = nums[j++];
            }else {
                temp[index++] = nums[i++];
            }
        }

        while(i <= mid){
            temp[index++] = nums[i++];
        }

        while (j <= right){
            temp[index++] = nums[j++];
        }

        index = 0;
        while (left <= right){
            nums[left++] = temp[index++];
        }
    }
}