C++ 알고리즘 - 백준 1269 대칭 차집합

https://www.acmicpc.net/problem/1269

 

#include <bits/stdc++.h>
#include <unordered_map>
#define endl "\n"

using namespace std;

void CPP_INIT() {
	ios::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
}

int main(void) {
	CPP_INIT();

	int input1, input2;
	int num;

	unordered_map<int, bool> um;

	cin >> input1 >> input2;

	for (int i = 0; i < input1 + input2; i++) {
		cin >> num;
		if (um[num] != true)
			um[num] = true;
		else
			um.erase(num);
	}

	cout << um.size();
}