3910033_wa.cpp

北大大牛代码 1240道题的原代码 超级权威

#include <stdio.h>
#include <algorithm>

using namespace std;

struct node
{
	int st, ed;

	bool operator < (const node t)	const
	{
		if (st != t.st)
		{
			return st < t.st;
		}
		else
		{
			return ed > t.ed;
		}
	}
}cow[25000];

int main()
{
	int n, t, i, j, ans = 0, max;

	scanf("%d%d", &n, &t);
	for (i = 0; i < n; i++)
	{
		scanf("%d%d", &cow[i].st, &cow[i].ed);
	}
	sort(cow, cow + n);
	for (i = 0; i < n; i++)
	{
		j = i;
		ans++;
		if (cow[i].ed >= t)
			break;
		max = 0;
		while (j < n && cow[j].st <= cow[i].ed)
		{
			if (cow[j].ed > max)
			{
				max = cow[j].ed;
			}
			j++;
		}
		if (j == i + 1)
		{
			ans = -1;
			break;
		}
		i = j - 1;
	}
	printf("%d", ans);
	return 0;
}