题目描述I won’t feel lonely, nor will I be sorrowful… not before everything is buried. A string of $n$ beads is left as the message of leaving. The beads are numbered from $1$ to $n$ from left to right, e

题目描述Once, Leha found in the left pocket an array consisting of $n$ integers, and in the right pocket $q$ queries of the form $l$ $r$ $k$. If there are queries, then they must be answered. Answer for t

题目描述There are $n$ balls. They are arranged in a row. Each ball has a color (for convenience an integer) and an integer value. The color of the $i$-th ball is $c_i$ and the value of the $i$-th ball is

题目描述Vasya is studying number theory. He has denoted a function $f(a, b)$ such that: $f(a, 0)=0$; $f(a, b)=1+f(a, b-(a, b))$, where $(a, b)$ is the greatest common divisor of $a$ and $b$. V

题目描述The Great Mushroom King descended to the dwarves, but not everyone managed to see him. Only the few chosen ones could see the King. We know that only $LCM(k^{2^l}+1, k^{2^{l+1}}+1, \ldots, k^{2^r}

题目描述Sereja has a sequence that consists of $n$ positive integers, $a_1, a_2, \ldots, a_n$. First Sereja took a piece of squared paper and wrote all distinct non-empty non-decreasing subsequences of se

题目描述Vasya has a set of $4n$ strings of equal length, consisting of lowercase English letters “a”, “b”, “c”, “d” and “e”. Moreover, the set is split into $n$ groups of $4$ equal strings each. Vasya als

题目描述$n$ people are standing on a coordinate axis in points with positive integer coordinates strictly less than $10^6$. For each person we know in which direction (left or right) he is facing, and his

题目描述In the Isle of Guernsey there are $n$ different types of coins. For each $i \ (1 \le i \le n)$, coin of type $i$ is worth $a_i$ cents. It is possible that $a_i=a_j$ for some $i$ and $j \ (i \

题目描述Farmer John has just given the cows a program to play with! The program contains two integer variables, $x$ and $y$, and performs the following operations on a sequence $a_1, a_2, \ldots, a_n$ of