According to me following are the standard algorithms:

1. DP / Greedy

2. DFS/BFS

4. Sorting/Binary Search/ Data Structures like maps and sets 4. Maths (Basic not FFt or something)

Although these algorithms are sufficient to become candidate master and 5 star if one has speed and accuracy but I believe I will need to learn some advanced algorithms to further increase the level. Can somebody please share the algorithms which are most occurring in 4th/5th question of Codeforces Div 2 round and 2nd/3rd question of codechef div 1 cookoff.

Range query DS like

segment tree, BITetcI've solved more than a few Div2Ds and a few div2Es but never encountered either of these.