*LEEDCODE 912排序数组

class Solution {
public:

    vector<int> sortArray(vector<int>& nums) {
        Heapsort(nums);
        return nums;
    }
    void Heapsort(vector<int>& nums)
    {
        int n = nums.size();
        for(int i = (n/2) - 1; i>=0; i--)
        {
            Adjustdown(nums, i, n);
        }
        for(int i = n-1; i>=0; i--)
        {
            swap(nums[0], nums[i]);
            Adjustdown(nums, 0, i);  
        }


    }
    void Adjustdown(vector<int>& nums, int root, int n)
    {
        int lson = 2 * root + 1;
        while(lson < n)
        {
            if((lson + 1) < n && nums[lson] < nums[lson + 1])
            {
                lson = lson + 1;
            }
            if(nums[lson] > nums[root])
            {
                swap(nums[lson], nums[root]);
                root = lson;
                lson = 2 * root + 1;
            }
            else
                break;
        }
    }
    void swap(int& a, int& b)
    {
        int tmp;
        tmp = a;
        a = b;
        b = tmp;
    }
    
};

堆排序

分两步：

1 大顶堆

2 有序的剩余元素、自上而下