每日一题洛谷P8637 [蓝桥杯 2016 省 B] 交换瓶子c++

#include<iostream>
#include<vector>
#include<cmath>
using namespace std;
int main() {
	int n;
	cin >> n;
	vector<int> s(n + 1);
	for (int i = 1; i <= n; i++)cin >> s[i];
	int count = 0;
	int i = 1;
	while (i <= n) {
		if (s[i] != i) {
			count++;
			swap(s[i], s[s[i]]);
		}
		else i++;
	}
	cout << count << endl;
	return 0;
}