寻找数组中第K大的数字-快排解法（Python3）

给定一个数组A，寻找第k大的数字。

本质上是查询操作，但是却使用到快排思想（即分治）

A = [-1, 3, -2, 4, -5];

def partition(A: int, low: int, high: int) -> int:
    temp = A[low];
    while low < high:
        while low < high and temp >= A[high]:
            high -= 1;
        A[low] = A[high];
        while low < high and temp < A[low]:
            low += 1;
        A[high] = A[low];
    A[low] = temp;
    return low;

def quciksort(A: int, low: int, high: int, k: int) -> int:
    if low <= high:
        pos = partition(A, low, high);
        if pos == k - 1:
            return A[pos];
        elif pos > k - 1:
            return quciksort(A, low, pos-1, k);
        elif pos < k - 1:
            return quciksort(A, pos+1, high, k);
    else:
        return -1;

print(quciksort(A, 0, len(A)-1, 5));