Codeforces Round 157 (Div. 1)

5 problems from Codeforces Round 157 (Div. 1) (contest 258), difficulty 1100-2600. 3/5 solutions verified against sample I/O.

5 items

Codeforces Round 157 (Div. 1)

Div. 1 | 5 problems | 3/5 verified | Difficulty 1100-2600 | 8m 42s

# Problem Rating Tags Accepted Time ✓
A Little Elephant and Bits 1100 greedy, math 26,500 1m 29s ✓
B Little Elephant and Elections 1900 brute-force, combinatorics, dp 1,604 51s
C Little Elephant and LCM 2000 binary-search, combinatorics, dp 1,986 3m 51s ✓
D Little Elephant and Broken Sorting 2600 dp, math, probabilities 1,421 1m 27s ✓
E Little Elephant and Tree 2400 data-structures, dfs-and-similar, trees 1,317 1m 4s
Practice › Codeforces Solutions › Codeforces Round 157 (Div. 1) ›

CF 258A - Little Elephant and Bits

We are given a binary number as a string, representing an integer in base 2, and we are allowed to delete exactly one digit. The goal is to choose which digit to remove so that the resulting binary number, when interpreted as a decimal integer, is as large as possible.
codeforces competitive-programming greedy math Jun 4, 2026
Practice › Codeforces Solutions › Codeforces Round 157 (Div. 1) ›

CF 258C - Little Elephant and LCM

We are given an array a. For every position i, we must choose an integer bi such that 1 ≤ bi ≤ ai. A sequence b is called good when its least common multiple is equal to its maximum element.
codeforces competitive-programming binary-search combinatorics dp math Jun 4, 2026
Practice › Codeforces Solutions › Codeforces Round 157 (Div. 1) ›

CF 258E - Little Elephant and Tree

We are given a rooted tree with n nodes, where node 1 is the root. Each node contains a list of numbers that starts empty. We then perform m operations.
codeforces competitive-programming data-structures dfs-and-similar trees Jun 4, 2026
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CF 258D - Little Elephant and Broken Sorting

We are given a permutation of integers from 1 to n and a sequence of m swap operations. Normally, these operations would sort the array into ascending order, but the swap program is broken: each move either swaps the indicated positions or does nothing, each with probability 1/2.
codeforces competitive-programming dp math probabilities Jun 4, 2026
Practice › Codeforces Solutions › Codeforces Round 157 (Div. 1) ›

CF 258B - Little Elephant and Elections

Codeforces 258B: Little Elephant and Elections
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