These are my answers for a codeforces problem and I don't know why the first snippet gives a wrong answer.

The second is accepted though.

I want to know if there is a problem with the judgment test cases because they seem to give the same output.

The problem says the following:

Given the boundaries of 2 intervals. Print the boundaries of their intersection.

Note: Boundaries mean the two ends of an interval which are the starting number and the ending number.

Input: Only one line contains two intervals [l1,r1], [l2,r2] where (1≤l1,l2,r1,r2≤109), (l1≤r1,l2≤r2).

It's guaranteed that l1≤r1 and l2≤r2.

Output: If there is an intersection between these 2 intervals print its boundaries , otherwise print -1.

Snippet 1

#include <bits/stdc  .h>

using namespace std;

int main()
{
    int a, b, c, d;
    int z;
    cin >> a >> b >> c >> d;
    if(a > b)
    {
        z = a;
        a = b;
        b = z;
    }
    if(c > d)
    {
        z = c;
        c = d;
        d = z;
    }
    if(c > b)
    {
        cout << -1;
    }
    else
    {
        cout << max(a, c) << " " << min(b, d);
    }
    return 0
}

Snippet 2

#include <bits/stdc  .h>
using namespace std;

int main()
{
    int l1 , r1 , l2 , r2;
    cin >> l1 >> r1 >> l2 >> r2;
    int _begin = max(l1,l2);
    int _end = min(r1,r2);
    if (_begin > _end)
        cout << -1;
    else
        cout << begin << " " << end;
    return 0;
}

CodePudding user response：

In the first program you are checking only one condition

if(c > b)
{
    cout << -1;
}

But you need to check also the following condition

if ( d < a )
{
    cout << -1;
}

For example

if(c > b || d < a )
{
    cout << -1;
}
else
{
    //...
}