Try this test:
5
2 10
2 4
3 4
6 9
7 8
11
1
2
3
4
5
6
7
8
9
10
11

Answer:
-1
2
3
3
1
4
5
5
4
1
-1

My code passes this test... Still getting WA5.

The following test helped me to get AC:
7
2 8
2 6
3 3
6 6
7 7
8 8
9 10
10
1
2
3
4
5
6
7
8
9
10
Answer:
-1
2
3
2
2
4
5
6
7
7
I used points sorting + stack approach. My error was in sorting function: I didn't handle situation when points have the same coordinates, the same types, but belong to different segments. Once I added condition which deals with segment numbers, I got AC.
By the way, different compilers may give different results: my program compiled with visual studio gave correct results, while g++ did not.

Edited by author 05.01.2020 20:01