Codeforces Round 129 (Div. 1)

Solutions for Codeforces Round 129 (Div. 1) (contest 204). 4/5 problems verified against sample I/O. Difficulty range: 1500-2800.

5 items

Codeforces Round 129 (Div. 1)

Type: Div. 1 | Problems: 5 | Verified: 4/5 | Rating range: 1500-2800 | Time: 5m 54s

Problem	Name	Rating	Tags	Solve Time	Verified
A	Little Elephant and Interval	1500	binary-search, combinatorics, dp	1m 39s	✓
B	Little Elephant and Cards	1500	binary-search, data-structures	1m 8s	✓
C	Little Elephant and Furik and Rubik	2000	math, probabilities	1m 23s	✗
D	Little Elephant and Retro Strings	2400	dp	59s	✓
E	Little Elephant and Strings	2800	data-structures, implementation, string-suffix-structures	45s	✓

Practice › Codeforces Solutions › Codeforces Round 129 (Div. 1) ›

CF 204A - Little Elephant and Interval

We are asked to count the numbers in a given interval [l, r] where the first digit equals the last digit. The input consists of two integers l and r, defining the interval. The output is a single integer, the count of numbers satisfying this property.

Practice › Codeforces Solutions › Codeforces Round 129 (Div. 1) ›

CF 204B - Little Elephant and Cards

We have a collection of cards, each with a front color and a back color. Initially, all cards lie with the front side up. The goal is to make at least half of the cards show the same color on the upper side.

Practice › Codeforces Solutions › Codeforces Round 129 (Div. 1) ›

CF 204C - Little Elephant and Furik and Rubik

We are given two strings of equal length. From each string we independently pick a substring, and both substrings must have the same length. After choosing them, we compare them character by character and count how many positions match.

Practice › Codeforces Solutions › Codeforces Round 129 (Div. 1) ›

CF 204D - Little Elephant and Retro Strings

We are given a string consisting of three possible characters: fixed black cells, fixed white cells, and unknown cells that we are free to assign either color.

Practice › Codeforces Solutions › Codeforces Round 129 (Div. 1) ›

CF 204E - Little Elephant and Strings

We are given a list of strings, and for each string, we need to count the number of its substrings that appear in at least k strings from the list. A substring is any contiguous segment of a string.