#include<iostream>
using namespace std;
int main()
{
	unsigned long int i, road, num, n, m;
		bool tree[2000000001];

	for (i = 0; i <= 2000000001; i++)
		tree[i] = true;
	cin >> road >> num;
	while (num--)
	{
		cin >> n >> m;
		for (i = n; i <= m; i++)
			tree[i] = false;
	}
	int count = 0;
	for (i = 0; i <= road; i++)
		if (tree[i]) count++;
	cout << count << endl;
	return 0;
}

• Re:请问我这个哪里错了 (472) 2016gdgzoi467 2017-05-28 11:58:13