乔治与住宿#acm刷题

codeforce-467a（乔治与住宿）

题目：
George has recently entered the BSUCP (Berland State University for Cool Programmers). George has a friend Alex who has also entered the university. Now they are moving into a dormitory.

George and Alex want to live in the same room. The dormitory has n rooms in total. At the moment the i-th room has pi people living in it and the room can accommodate qi people in total (pi ≤ qi). Your task is to count how many rooms has free place for both George and Alex.

input:
The first line contains a single integer n (1 ≤ n ≤ 100) — the number of rooms.

The i-th of the next n lines contains two integers pi and qi (0 ≤ pi ≤ qi ≤ 100) — the number of people who already live in the i-th room and the room’s capacity.

output
Print a single integer — the number of rooms where George and Alex can move in.

Examples
input
3
1 1
2 2
3 3
Output
0
Input
3
1 10
0 10
10 10
Output
2

问题连接：
https://vjudge.net/problem/CodeForces-467A
问题简述：
求出n间宿舍中还能容纳两人的房间。
问题分析:
程序要用到循环和判断语句，并应设置一个计数器记录符合要求的房间。

AC通过的c++程序如下：

#include <iostream>
using namespace std;
int main()
{
	int n = 0, p = 0, q = 0, i = 0;
	cin >> n;
	for (int j = 1; j <= n; j++)
	{
		cin >> p >> q;
		if (p > q || p < 0 || p>100 || q <= 0 || q > 100)
			break;
		if (q - p >= 2)
		{
			i++;
		}
	}
	cout << i;
	return 0;
}