问题 K: 2008J-阅读2-快排-找第k大的数

#include <iostream>  
using namespace std;  
  
int a[1000001],n,ans = -1;  
void swap(int &a,int &b){  
    int c;  
    c = a; a = b; b = c;  
}  
int FindKth(int left, int right, int n){  
    int tmp,value,i,j;  
    if (left == right) return left;  
    tmp = rand()% (right - left) + left;  
    swap(a[tmp],a[left]);  
    value =[       ①       ];  
    i = left;  
    j = right;  
    while (i < j){  
        while (i < j && [       ②       ]) j --;  
        if (i < j) {a[i] = a[j]; i ++;} else break;  
        while (i < j && [       ③     ]) i ++;  
        if (i < j) {a[j] = a[i]; j - -;} else break;  
    }  
    [      ④       ]    
    if (i < n) return  FindKth([         ⑤        ] );  
    if (i > n) return [         ⑥           ]          
    return i;  
}  
int main(){  
    int i;  
    int m = 1000000;  
    for (i = 1;i <= m;i ++)  
        cin >> a[i];  
    cin >> n;  
    ans = FindKth(1,m,n);  
    cout << a[ans];  
    return 0;  
}  

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