
Problem Name 
Online Judge 
Contest 
Difficulty Level 
1 
Bear and Prime 100 
Codeforces 
Codeforces Round #356 (Div. 1) & Codeforces Round #356 (Div. 2) 
2 
2 
Guess the Array 
Codeforces 
Technocup 2017  Elimination Round 1 (Unofficially Open for Everyone, Rated for Div. 2) 
4 
3 
Interactive LowerBound 
Codeforces 
AIM Tech Round 4 (Div. 1) & AIM Tech Round 4 (Div. 2) 
5 
4 
Pick Heroes 
Codeforces 
Mail.Ru Cup 2018 Round 3 
5 
5 
Mahmoud and Ehab and the binary string 
Codeforces 
Codeforces Round #435 (Div. 2) 
6 
6 
Searching Rectangles 
Codeforces 
Codeforces Round #371 (Div. 1) & Codeforces Round #371 (Div. 2) 
6 
7 
Glad to see you! 
Codeforces 
Codeforces Round #415 (Div. 1) & Codeforces Round #415 (Div. 2) 
6 
8 
Subway Pursuit 
Codeforces 
Codeforces Round #507 (Div. 1, based on Olympiad of Metropolises) & Codeforces Round #507 (Div. 2, based on Olympiad of Metropolises) 
6 
9 
Vladik and Favorite Game 
Codeforces 
Codeforces Round #416 (Div. 2) 
6 
10 
Divisors 
Codeforces 
Lyft Level 5 Challenge 2018  Elimination Round 
6 
11 
Interactive Bulls and Cows (Easy) 
Codeforces 
Testing Round #13 
7 
12 
Something with XOR Queries 
Codeforces 
Technocup 2018  Elimination Round 2 
7 
13 
The penguin's game 
Codeforces 
Codeforces Round #427 (Div. 2) 
8 
14 
Lost Root 
Codeforces 
Codeforces Round #523 (Div. 2) 
9 
15 
Interactive Bulls and Cows (Hard) 
Codeforces 
Testing Round #13 
9 