I also got WA for test 4.....so I started to try some self made test cases.....and I came across this one :
5 4
2 0 1 3
My output : NO.
Correct Output should be YES.

I will have to rethink my approach.....maybe you have the same problem as well.

case 3 3 1 2 3 helped me in test 4.
But anyway it's better to write your own test case generator.

Edited by author 18.04.2020 04:47

7 4
2 5 7 5