I was recently solving (https://codeforces.com/contest/1900/problem/C) . I did DFS approach first https://codeforces.com/contest/1900/submission/239489864. But it gave TLE on testcase 5 but when did using BFS 239489864. It got accepted but why? Both are just brute force yet one works not other. Please help

Hi, I just started giving contest although I had been practicing for about 4-5 months. My problem is whenever I give a contest the timer increases the pressure on me and I tend to make mistakes in problem that I can easily solve in practice mode. Someone suggested me that I should take virtual contest on daily basis to get rid of time pressure but this doesn't just feel right to me. What do you suggest I should do?