Codeforces Round 120 (Div. 2)

5 problems from Codeforces Round 120 (Div. 2) (contest 190), difficulty 1100-2100. 1/5 solutions verified against sample I/O.

5 items

Codeforces Round 120 (Div. 2)

Div. 2 | 5 problems | 1/5 verified | Difficulty 1100-2100 | 4m 25s

# Problem Rating Tags Accepted Time ✓
A Vasya and the Bus 1100 greedy, math 6,259 21s
B Surrounded 1800 geometry 3,092 1m 24s ✓
C STL 1500 dfs-and-similar 3,225 43s
D Non-Secret Cypher 1900 two-pointers 2,660 24s
E Counter Attack 2100 data-structures, dsu, graphs 1,737 1m 33s
Practice › Codeforces Solutions › Codeforces Round 120 (Div. 2) ›

CF 190A - Vasya and the Bus

We are asked to compute the minimum and maximum bus fare collected given a number of grown-ups n and children m on a bus. Each grown-up pays one ruble for themselves, and each grown-up can take at most one child for free. Any additional children cost one ruble each.
codeforces competitive-programming greedy math Jun 3, 2026
Practice › Codeforces Solutions › Codeforces Round 120 (Div. 2) ›

CF 190B - Surrounded

We are given two circular “threat zones” on a plane. Each one is defined by a center point and a radius. The center is a city, and the radius describes how far the enemy ring extends from that city. We are allowed to place a single radar anywhere in the plane.
codeforces competitive-programming geometry Jun 3, 2026
Practice › Codeforces Solutions › Codeforces Round 120 (Div. 2) ›

CF 190E - Counter Attack

We are given a set of cities, but the twist is that the input does not describe the real road system directly. Instead, it describes the complement of it.
codeforces competitive-programming data-structures dsu graphs hashing sortings Jun 3, 2026
Practice › Codeforces Solutions › Codeforces Round 120 (Div. 2) ›

CF 190D - Non-Secret Cypher

We are given a sequence of integers and a threshold value $k$. The task is to count how many contiguous subarrays contain some value that appears at least $k$ times inside that subarray.
codeforces competitive-programming two-pointers Jun 3, 2026
Practice › Codeforces Solutions › Codeforces Round 120 (Div. 2) ›

CF 190C - STL

We are given a sequence of tokens that were spoken in order, each token being either int or pair. These tokens are supposed to form a valid nested type expression of a very specific grammar.
codeforces competitive-programming dfs-and-similar Jun 3, 2026