Hello Codeforces!
Today I was solving 1038E - Наибольшее паросочетание during practice. I made submission 107130992. To my big surprise, it got AC with time 951 ms (less than half of TL). However, I have an easy-to-generate test which makes it work around 3000 ms! This indicates that the testcases are extremely weak.
The test is very simple: we can just distribute the 100 blocks evenly between all 6 kinds of pairs with distinct elements.
It's also interesting that it is possible to make that submission work fast enough even on that test (see 107131735). This means that one can wrongly get AC while being on the right track.
I know that this is quite an old problem. However, it might still be worth to throw in a few more tests so that such solutions made during practice do get TLE.
Tagging the problem author: Ashishgup