
Problem Name 
Online Judge 
Contest 
Difficulty Level 
1 
Dima and Lisa 
Codeforces 
Codeforces Round #324 (Div. 2) 
2 
2 
Taxes 
Codeforces 
Codeforces Round #382 (Div. 2) & Codeforces Round #382 (Div. 1) 
2 
3 
Troublemakers 
UVA 

4 
4 
Interactive LowerBound 
Codeforces 
AIM Tech Round 4 (Div. 1) & AIM Tech Round 4 (Div. 2) 
5 
5 
Ghd 
Codeforces 
Codeforces Round #213 (Div. 1) 
8 
6 
Oranges and Apples 
Codeforces 
Codeforces Beta Round #23 
8 
7 
Lost Root 
Codeforces 
Codeforces Round #523 (Div. 2) 
9 
8 
Digits 
Codeforces 
Bubble Cup X  Finals [Online Mirror] 
9 