Codeforces Round 271 (Div. 2)

6 problems from Codeforces Round 271 (Div. 2) (contest 474), difficulty 900-2100. 6/6 solutions verified against sample I/O.

6 items

Codeforces Round 271 (Div. 2)

Div. 2 | 6 problems | 6/6 verified | Difficulty 900-2100 | 9m 19s

# Problem Rating Tags Accepted Time ✓
A Keyboard 900 implementation 54,639 1m 4s ✓
B Worms 1200 binary-search, implementation 62,480 1m 36s ✓
C Captain Marmot 2000 brute-force, geometry 3,385 1m 12s ✓
D Flowers 1700 dp 30,615 1m 50s ✓
E Pillars 2000 binary-search, data-structures, dp 4,169 2m 1s ✓
F Ant colony 2100 data-structures, math, number-theory 11,583 1m 36s ✓
Practice › Codeforces Solutions › Codeforces Round 271 (Div. 2) ›

CF 474A - Keyboard

The problem presents a keyboard with three rows of characters arranged exactly like a standard QWERTY layout. Mole is typing messages on this keyboard, but he accidentally shifted his hands either one key to the left or one key to the right.
codeforces competitive-programming implementation May 30, 2026
Practice › Codeforces Solutions › Codeforces Round 271 (Div. 2) ›

CF 474B - Worms

We are given several piles of worms arranged in order. The worms are numbered consecutively across all piles. If the pile sizes are: then the first pile contains worms numbered 1 through 2, the second pile contains worms numbered 3 through 9, and the third pile contains worms…
codeforces competitive-programming binary-search implementation May 30, 2026
Practice › Codeforces Solutions › Codeforces Round 271 (Div. 2) ›

CF 474C - Captain Marmot

We are asked to help Captain Marmot organize his regiments of moles so that each group of four forms a perfect square on a plane. Each mole starts at a position (xi, yi) and has a “home” at (ai, bi).
codeforces competitive-programming brute-force geometry May 30, 2026
Practice › Codeforces Solutions › Codeforces Round 271 (Div. 2) ›

CF 474D - Flowers

A dinner is represented as a sequence of flowers. A red flower contributes length 1, while white flowers are special: they may only appear in contiguous groups of exactly k flowers.
codeforces competitive-programming dp May 30, 2026
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CF 474E - Pillars

We have a sequence of pillars arranged from left to right. Pillar i has height h[i]. A valid jump can only go forward, from a smaller index to a larger index, and the height difference between the two pillars must be at least d.
codeforces competitive-programming binary-search data-structures dp sortings trees May 30, 2026
Practice › Codeforces Solutions › Codeforces Round 271 (Div. 2) ›

CF 474F - Ant colony

We are given a line of ants, each with an integer strength. Mole wants to observe fights among ants in specified contiguous segments of the line. For a given segment from position l to r, every ant fights every other ant within that segment.
codeforces competitive-programming data-structures math number-theory May 30, 2026