1 
P1  Cumulative Sum Query 
SPOJ 

2 
P2  Pasha and String 
Codeforces 
Codeforces Round #297 (Div. 2) 
3 
P3  Kuriyama Mirai's Stones 
Codeforces 
Codeforces Round #248 (Div. 2) 
4 
P4  Tell me the frequencies! 
UVA 

5 
P5  Maximum Absurdity 
Codeforces 
Codeforces Round #193 (Div. 2) 
6 
P6  Anya and Smartphone 
Codeforces 
Codeforces Round #293 (Div. 2) 
7 
P7  Removing Columns 
Codeforces 
Codeforces Round #283 (Div. 2) & Codeforces Round #283 (Div. 1) 
8 
P8  Valera and Contest 
Codeforces 
Codeforces Round #216 (Div. 2) 
9 
P9  Little Frog 
Codeforces 
Codeforces Beta Round #49 (Div. 2) 
10 
P10  Vasya and Basketball 
Codeforces 
Codeforces Round #281 (Div. 2) 
11 
P11  Multitasking 
Codeforces 
Codeforces Round #225 (Div. 2) 
12 
P12  Ladder 
Codeforces 
Codeforces Round #171 (Div. 2) 
13 
P13  Diverse Permutation 
Codeforces 
Codeforces Round #275 (Div. 1) & Codeforces Round #275 (Div. 2) 
14 
P14  Little Elephant and Bits 
Codeforces 
Codeforces Round #157 (Div. 1) & Codeforces Round #157 (Div. 2) 
15 
P15  Building Permutation 
Codeforces 
Codeforces Round #175 (Div. 2) 