大佬求助猴子排序为啥不能过（doge）

#include<bits/stdc++.h>
using namespace std;
unsigned long long n, a[100005], b[100005], c[100005], flag[100005];
bool check(){
	for(int i = 1;i < n;i++) if(a[i] < a[i - 1]) return 0;
	return 1;
}
int main(){
	srand(time(NULL));
	cin >> n;
	for(int i = 0;i < n;i++) cin >> a[i];
	do{
		for(int i = 0;i < n;i++) flag[i] = 0;
		for(int i = 0; i < n;i++) {
			do {
				b[i] = (rand() * rand()) % n;
			}while(flag[b[i]]);
			flag[b[i]] = 1;
		}
		for(int i = 0;i < n;i++) c[b[i]] = a[i];
		for(int i = 0;i < n;i++) a[i] = c[i];
	}while(!check());
	for(int i = 0;i < n;i++) cout << a[i] <<" ";
	return 0;
}