백준 3077번 임진왜란 (C++)

#include <iostream>
#include <vector>
#include<map>

using namespace std;

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	int n;
	cin >> n;

	string s;
	map<string, int>m;

	for (int i = 0; i < n; i++) {
		cin >> s;
		m[s] = i;
	}

	vector<string>ans;
	for (int i = 0; i < n; i++) {
		cin >> s;
		ans.push_back(s);
	}
	
	string p, q;
	int cnt = 0;
	for (int i = 0; i < n; i++) {
		p = ans[i];
		for (int j = i + 1; j < n; j++) {
			q = ans[j];
			if (m[p] < m[q])cnt++;
		}
	}

	int amount = n * (n - 1) / 2;

	cout << cnt << '/' << amount;

}