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Codeforces Round #267 (Div. 2) A. George and Accommodation

2024-07-23 08:02:30   221人阅读

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 haspi people living in it and the room can accommodateqi 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 andqi(0?≤?pi?≤?qi?≤?100) — the number of people who already live in thei-th room and the room‘s capacity.

Output

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

Sample test(s)
Input
3
1 1
2 2
3 3
Output
0
Input
3
1 10
0 10
10 10
Output
2题意：有n个寝室，一共可以住qi,已经住了pi个，问再来两个可以住进去几个寝室思路：直接计算的大水题
#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

int main() {
	int n;
	scanf("%d", &n);
	int p, q, ans = 0;
	for (int i = 0; i < n; i++) {
		scanf("%d%d", &q, &p);
		if (p - q >= 2)
			ans++;
	}
	printf("%d\n", ans);
	return 0;
}

 

Codeforces Round #267 (Div. 2) A. George and Accommodation


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