Gym 101911c bacteria (minimum stack)

The question ：n Elements , Choose two identical elements at a time , If there is no , Add a new , Then put the sum of the two numbers back into the original sequence , Ask if there is only one element left , And how many are added .

Answer key ： The smallest pile
Just simulate the process of taking .

#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<cstdio>
#include<string>
#include<cstring>
#include<algorithm>
#include<queue>
#include<stack>
#include<cmath>
#include<vector>
#include<fstream>
#include<set>
#include<map>
#include<sstream>
#include<iomanip>
#define ll long long
#define pii pair<int, int>
using namespace std;
const int maxn = 2e5 + 5;
int n, x;
ll a, b;
priority_queue<ll, vector<ll>, greater<ll> > q;
int main() {
    
	scanf("%d", &n);
	for (int i = 1; i <= n; i++) {
    
		scanf("%d", &x);
		q.push(x);
	}
	int ans = 0;
	x = 0;
	while (q.size()) {
    
		++x;
		if (x == 2 * maxn) {
    
			ans = -1; 
			break;
		}
		a = q.top();
		q.pop();
		if (q.empty()) break;
		b = q.top();
		if (a == b) {
    
			q.pop();
			q.push(2ll * a);
		}
		else {
    
			ans++;
			q.push(2ll * a);
		}
	}
	printf("%d\n", ans);
	return 0;
}