查找数组的第k小元素

int findPivorIdx(int A[], int k, int low, int high) {
 
    int pivor = A[low];
    while (low<high)
    {
        while (A[high]>=pivor && low<high)
        {
            high--;
        }
        A[low] = A[high];
 
        while (A[low]<pivor && low<high)
        {
            low++;
        }
        A[high] = A[low];
    }
 
    A[low] = pivor;
 
    return low;
}
 
int findKMin(int A[],int k, int low, int high) {
 
    if (low<high) // 继续查找
    {
        int pId = findPivorIdx(A,k,low,high);
        if ((pId+1)==k) // 找到了
        {
            return A[pId];
        }else if((pId+1)<k) { // 还在右边
            return findKMin(A,k,pId+1,high); // 对右边递归
        }else if((pId+1)>k){
            return findKMin(A,k,low,pId-1); // 对左边递归
        }
    }
 
    else { // 返回low
        return A[low];
    }
}