Codeforces Round 489 (Div. 2)

2 problems from Codeforces Round 489 (Div. 2) (contest 992), difficulty 800-1600. 2/2 solutions verified against sample I/O.

2 items

Codeforces Round 489 (Div. 2)

Div. 2 | 2 problems | 2/2 verified | Difficulty 800-1600 | 2m 25s

#	Problem	Rating	Tags	Accepted	Time	✓
A	Nastya and an Array	800	implementation, sortings	14,315	1m 8s	✓
B	Nastya Studies Informatics	1600	math, number-theory	6,766	1m 17s	✓

Practice › Codeforces Solutions › Codeforces Round 489 (Div. 2) ›

CF 992A - Nastya and an Array

We are given a list of integers, and we are allowed to repeatedly apply an operation that changes the array in a very specific way: in one move, we choose an integer value and add it to every element that is currently non-zero. Zeros stay untouched during that operation.

Practice › Codeforces Solutions › Codeforces Round 489 (Div. 2) ›

CF 992B - Nastya Studies Informatics

We are given four integers $l, r, x, y$. The task is to count ordered pairs $(a, b)$ such that both numbers lie inside the interval $[l, r]$, and their greatest common divisor is exactly $x$ while their least common multiple is exactly $y$.