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George and Accommodation
Problem Description: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 hasnrooms in total. At the moment thei-th room haspipeople living in it and the room can accommodateqipeople 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 integern(1 ≤n≤ 100)— the number of rooms.
Thei-th of the nextnlines contains two integerspiandqi(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.
Examples
Input
3
1 1
2 2
3 3
Output
0
Input
3
1 10
0 10
10 10
Output
2
问题链接：https://vjudge.net/problem/CodeForces-467A
问题简述：输入总宿舍数量，输入宿舍已有人数和宿舍总可居住人数，判断剩余可居住人数是否大于2
问题分析：利用二维数组存储数据，判断数据之差是否大于2，循环总数量次，求出可选房间数总和。
AC通过的C++语言程序如下：

#include <iostream>
using namespace std;
int main()
{
    int num;
    cin >> num;
    int **p = new int*[num];
    for (int i = 0; i < num; i++)
    {
        p[i] = new int[2];
    }//相当于声明了一个p[mun][2]二维数组
    int a = 0, b = 0;
    int sl;
    while (cin >> sl)
    {
        p[a][b] = sl;
        b++;
        if (b == 2)
        {
            b = 0;
            a++;
        }
        if (a == num)
            break;
    }
    int fj = 0;
    for (int i = 0; i < num; i++)
    {
        if (p[i][1] - p[i][0] >= 2)
        {
            fj++;
        }
    }
    cout << fj;
}