
Problem Name 
Online Judge 
Contest 
Difficulty Level 
1 
Count on a tree 
SPOJ 

1 
2 
Kth Number 
SPOJ 

1 
3 
Dquery 
SPOJ 

1 
4 
To the moon 
SPOJ 

4 
5 
Persistent Bookcase 
Codeforces 
Codeforces Round #368 (Div. 2) 
5 
6 
Pathwalks 
Codeforces 
Divide by Zero 2018 and Codeforces Round #474 (Div. 1 + Div. 2, combined) 
6 
7 
Army Creation 
Codeforces 
Educational Codeforces Round 22 
7 
8 
Till I Collapse 
Codeforces 
Codeforces Round #406 (Div. 1) & Codeforces Round #406 (Div. 2) 
7 
9 
Functions On The Segments 
Codeforces 
Educational Codeforces Round 26 
9 