Topic Rating Link Solved Video
DFS and BFS (1200-1600) : https://codeforces.com/group/lRxLFtdNEC/contest/343563 11/11
Tree basics (1400-2200) : https://codeforces.com/gym/102694 03/06 https://youtu.be/MOy4UDjN8DM
Seg Tree (1600-2000) : https://vjudge.net/contest/454719 08/09 https://youtu.be/6V4vLieD--4
Seg Tree && Lazy propagation (1700-2400) : https://vjudge.net/contest/455776 09/12 https://youtu.be/7tZFG4tx5hQ
Fenwick Tree (BIT) (1700-2000) : https://vjudge.net/contest/456999 12/15 https://youtu.be/vtRS2fGm7V8