1 
P1  Multinomial Coefficients 
UVA 

2 
P2  The World is a Theatre 
Codeforces 
Codeforces Beta Round #95 (Div. 2) 
3 
P3  Array 
Codeforces 
Codeforces Beta Round #53 
4 
P4  Shaass and Lights 
Codeforces 
Codeforces Round #178 (Div. 2) 
5 
P5  Malek Dance Club 
Codeforces 
Codeforces Round #189 (Div. 1) & Codeforces Round #189 (Div. 2) 
6 
P6  Matrix 
Codeforces 
Codeforces Round #213 (Div. 1) & Codeforces Round #213 (Div. 2) 
7 
P7  Chocolate 
Codeforces 
Codeforces Round #340 (Div. 2) 
8 
P8  On Number of Decompositions into Multipliers 
Codeforces 
Codeforces Round #232 (Div. 1) & Codeforces Round #232 (Div. 2) 
9 
P9  Doom's Day 
UVA 

10 
P10  Vasya and Petya's Game 
Codeforces 
Codeforces Round #319 (Div. 1) & Codeforces Round #319 (Div. 2) 
11 
P11  Kyoya and Colored Balls 
Codeforces 
Codeforces Round #309 (Div. 1) & Codeforces Round #309 (Div. 2) 
12 
P12  Random Teams 
Codeforces 
Codeforces Round #273 (Div. 2) 
13 
P13  Pocket Book 
Codeforces 
Codeforces Round #108 (Div. 2) 
14 
P14  Modular Equations 
Codeforces 
Codeforces Round #282 (Div. 2) 
15 
P15  Mishka and trip 
Codeforces 
Codeforces Round #365 (Div. 2) 
16 
P16  Win or Freeze 
Codeforces 
Codeforces Round #107 (Div. 1) & Codeforces Round #107 (Div. 2) 
17 
P17  After Training 
Codeforces 
Codeforces Round #123 (Div. 2) 
18 
P18  Tiling with Hexagons 
Codeforces 
Codeforces Round #133 (Div. 2) 