Codeforces Round 139 (Div. 2)

Solutions for Codeforces Round 139 (Div. 2) (contest 225). 3/4 problems verified against sample I/O. Difficulty range: 1600-2200.

4 items

Codeforces Round 139 (Div. 2)

Type: Div. 2 | Problems: 4 | Verified: 3/4 | Rating range: 1600-2200 | Time: 9m 47s

Problem	Name	Rating	Tags	Solve Time	Verified
B	Well-known Numbers	1600	binary-search, greedy, number-theory	3m 27s	✗
C	Barcode	1700	dp, matrices	1m 54s	✓
D	Snake	2200	bitmasks, dfs-and-similar, graphs	58s	✓
E	Unsolvable	2100	math, number-theory	3m 28s	✓

Practice › Codeforces Solutions › Codeforces Round 139 (Div. 2) ›

CF 225B - Well-known Numbers

We are given two integers, s and k. The task is to express s as a sum of distinct numbers taken from the k-bonacci sequence. The sequence behaves like Fibonacci, but instead of summing the previous two values, each term is the sum of the previous k terms.

Practice › Codeforces Solutions › Codeforces Round 139 (Div. 2) ›

CF 225C - Barcode

We are given a grid of pixels with n rows and m columns. Every cell is either black () or white (.). We want to repaint the minimum number of cells so that the final picture satisfies two rules. First, every column must become monochromatic.

Practice › Codeforces Solutions › Codeforces Round 139 (Div. 2) ›

CF 225D - Snake

We are asked to simulate the movement of a snake on a small grid and determine the minimal number of moves required for the snake to reach an apple. The grid contains walls, empty squares, the snake itself, and one apple.

Practice › Codeforces Solutions › Codeforces Round 139 (Div. 2) ›

CF 225E - Unsolvable

The equation in the statement is $$leftlfloor frac{x}{y} rightrfloor + leftlfloor frac{y}{x} rightrfloor = z$$ and we want all positive integers $z$ for which this equation has no solution in positive integers $x,y$.