1931번: 회의실배정

#include <cstdio>

#include <utility>

#include <algorithm>

using namespace std;

typedef pair<int, int> pairInt;

int main()

{

int n, count = 0;

scanf("%d", &n);

pairInt *a = new pairInt[n];

for (int i = 0; i < n; ++i)

scanf("%d %d", &a[i].second, &a[i].first); //second가 시작, first가 끝나는시간

sort(a, a + n);

for (int i = 0, clock = -1; i < n; ++i)

if (a[i].second >= clock)

{

clock = a[i].first;

++count;

}

printf("%d", count);

}