【C++算法】分治——归并

排序数组

• 题目链接

排序数组https://leetcode.cn/problems/sort-an-array/description/

• 算法原理

• 代码步骤

class Solution {
    vector<int> tmp;
public:
    vector<int> sortArray(vector<int>& nums) 
    {
        tmp.resize(nums.size());
        merge(nums, 0, nums.size() - 1);
        return nums;
    }

    void merge(vector<int>& nums, int left, int right)
    {
        if(left >= right) return;
        int mid = (right + left) >> 1;
        merge(nums, left, mid);
        merge(nums, mid + 1, right);

        int i = 0, cur1 = left, cur2 = mid + 1;
        while(cur1 <= mid && cur2 <= right)
        {
            tmp[i++] = nums[cur1] <= nums[cur2] ? nums[cur1++] : nums[cur2++];
        }
        while(cur1 <= mid) tmp[i++] = nums[cur1++];
        while(cur2 <= right) tmp[i++] = nums[cur2++];
        for(int i = left; i <= right; i++)
        {
            nums[i] = tmp[i - left];
        }
    }
};