백준 2979번 C++

#include <iostream>

using namespace std;
const int MAX = 101;
int fare[MAX];

int main(void) {
	int answer = 0;
	int a, b, c;

	cin >> a >> b >> c;
	for (int i = 0; i < 3; i++) {
		int arrive, depart;
		cin >> arrive >> depart;
		for (int j = arrive; j < depart; j++) {
			fare[j] ++;
		}
	}
	for (int i = 1; i < MAX; i++) {
		if (fare[i] == 1)
			answer = answer + fare[i] * a;
		else if (fare[i] == 2)
			answer = answer + fare[i] * b;
		else if (fare[i] == 3)
			answer = answer + fare[i] * c;
	}
	cout << answer << endl;
	return 0;
}