题目讲解

LCR 159. 库存管理 III

本题的含义就是让求出最小的k个数

算法讲解

class Solution {
public:

    void my_qsort(vector<int>& nums, int l, int r)
    {
        if(l >= r) return ;
        int i = l, left = l-1, right = r+1;
        int key = nums[rand() % (r - l + 1) + l];
        //完成分三路  <key    == key    >key
        while(i < right)
        {
            if(nums[i] < key) swap(nums[++left], nums[i++]);
            else if(nums[i] == key) i++;
            else swap(nums[--right], nums[i]);
        }

        //分治这三路
        my_qsort(nums, l, left);
        my_qsort(nums, right, r);
    }

    vector<int> inventoryManagement(vector<int>& arr, int k) {
        //分三路-》直接快速排序-》 排升序
        srand(time(NULL));
        int n = arr.size();
        my_qsort(arr, 0, n-1);

        return {arr.begin(), arr.begin()+k};
    }
};