NOIP 2005 校门外的树

#include<iostream>
#include<cstring>
using namespace std;
int a[10005];

int main()
{
	memset(a, 1, sizeof(a));
	int l, m;
	cin >> l >> m;
	while (m--)
	{
		int start, end;
		cin >> start >> end;
		for (int i = start; i <= end; i++)
			a[i] = 0;
	}
	int cnt = 0;
	for (int i = 0; i <=l; i++)
	{
		if (a[i])
			cnt++;
	}
	cout << cnt << endl;
	return 0;
}

一道一维数组的水题，用一维数组存贮状态即可。后续只需要改变其值，最后统计一下剩余数目

http://noi.openjudge.cn/ch0106/solution/14325879/

未来还需要努力才行啊