Hello!

I'm new here, but for a long time following this forum. I got task for some project to do, but I really don't know how to start. If someone can help me, I would be grateful. I didn't do anything. I don't realize this task and I don't know how to start, I don't know what I need to do in this task, or anything. I need the whole code. If anyone can solve this, please help me, it's an emergency.

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You are given N open intervals on a line (the intervals do not include their endpoints). Your task is to write a program which finds the largest number of intervals that can be chosen so they don't intersect.

INPUT:

The first line of the standard input contains a number N (0<N<=5000), the number of intervals. The next N lines contain two integers li and ri (-10000< li < di <10000) which represent the left and right ends of the interval (1<=i<=N).

OUTPUT:

To the standard output in one line write the number of intervals which can be chosen so that they do not intersect.

Input:

4

-1 1

0 5

2 3

5 9

Output:

3

P.S. The program is required to implement function, which checks whether two intervals have a common point: bool check (int beg1, int end1, int beg2, int end2).I am suffering with this for a long time and I can not resolve it, the task should be solved using the iostream library.