In this question 822C - Hacker, pack your bags! , when I used set it gave TLE on test case 10 but when I used unordered_set, it got Accepted. I read some blogs where they told not to use unordered_set/map on CF as it can be hacked, so what should I do, should I use unordered set/map or not?

Submission 1 (TLE) : 256948385 Submission 2 (Accepted) : 256948457