HW2C

#include <iostream>
#include <cstdio>
#include <vector>

using namespace std;

int main()
{
    int N;
    cin >> N;
    vector <int> a(86401,0);
    int h1, m1, s1, h2, m2, s2;
    int input_in, input_out;

    for (int i = 0; i < N; i++) {
        scanf("%d:%d:%d %d:%d:%d", &h1, &m1, &s1, &h2, &m2, &s2);
        input_in = 3600*h1 + 60*m1 + s1;
        input_out = 3600*h2 + 60*m2 + s2;

        a[input_in] += 1;
        a[input_out + 1] -= 1;
    }

    int max = 0;
    int tmp = 0;
    for (int i = 0; i < 86400; i++) {
        tmp += a[i];
        if (tmp > max) {
            max = tmp;
        }
    }
    cout << max;
}