D. Mahmoud and a Dictionary time limit per test 4 seconds memory limit per test 256 megabytes input standard input output standard output Mahmoud wants to write a new dictionary that contains n words and relations between them. There are two types of…

Mad scientist Mike has constructed a rooted tree, which consists of n vertices. Each vertex is a reservoir which can be either empty or filled with water. The vertices of the tree are numbered from 1 to n with the root at vertex 1. For each vertex, t…

A. Oath of the Night's Watch time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output "Night gathers, and now my watch begins. It shall not end until my death. I shall take no wife, hold no lands,…

C. Mahmoud and a Message time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Mahmoud wrote a message s of length n. He wants to send it as a birthday present to his friend Moaz who likes strin…

Easy Summation                                                             Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others)                                                                                          …

C. Hard problem time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Vasiliy is fond of solving different tasks. Today he found one he wasn't able to solve himself, so he asks you to help. Vasil…

B. Mahmoud and a Triangle time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Mahmoud has n line segments, the i-th of them has length ai. Ehab challenged him to use exactly 3 line segments to…

A. Mahmoud and Longest Uncommon Subsequence time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output While Mahmoud and Ehab were practicing for IOI, they found a problem which name was Longest comm…

use fgets, and remove the potential '\n' in the string's last postion. (main point) remove redundancy there must be a stack, at first sight, you need a stack of type myNode, but think deeper, matrix multiplication is valid only if A.c=B.r, then the n…

for the backtracking part, thanks to the video of stanford cs106b lecture 10 by Julie Zelenski for the nice explanation of recursion and backtracking, highly recommended. in hdu 2553 cout N-Queens solutions problem, dfs is used. // please ignore, bel…