牛牛的排序 - 贪心 - 代码

#include <iostream>
#include <algorithm>
#include <vector>

using namespace std;

int n;
vector<int> a, b;

int calc() {
	if(a == b) return 0;
	if(a[0] == b[n - 1] && a[n - 1] == b[0]) return 3;
	if(a[0] != b[0] && a[n - 1] != b[n - 1]) return 2;
	return 1;
}

int main() {
	cin >> n;
	for(int i = 1; i <= n; i++) {
		int x; cin >> x;
		a.push_back(x);
		b.push_back(x);
	}
	sort(b.begin(), b.end());
	
	cout << calc() << endl;
	return 0;
}