Codeforces Round 138 (Div. 1)

5 problems from Codeforces Round 138 (Div. 1) (contest 223), difficulty 1700-3000. 1/5 solutions verified against sample I/O.

5 items

Codeforces Round 138 (Div. 1)

Div. 1 | 5 problems | 1/5 verified | Difficulty 1700-3000 | 9m 10s

# Problem Rating Tags Accepted Time ✓
A Bracket Sequence 1700 data-structures, expression-parsing, implementation 2,806 1m 48s ✓
B Two Strings 1900 data-structures, dp, strings 2,032 2m 39s
C Partial Sums 1900 combinatorics, math, number-theory 1,755 2m 19s
D Spider 3000 geometry, graphs 80 1m 17s
E Planar Graph 3000 flows, geometry, graphs 208 1m 7s
Practice › Codeforces Solutions › Codeforces Round 138 (Div. 1) ›

CF 223C - Partial Sums

Codeforces 223C: Partial Sums
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Practice › Codeforces Solutions › Codeforces Round 138 (Div. 1) ›

CF 223B - Two Strings

Codeforces 223B: Two Strings
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Practice › Codeforces Solutions › Codeforces Round 138 (Div. 1) ›

CF 223E - Planar Graph

We are given a connected planar graph drawn on the plane with no bridges, articulation points, loops, or multiple edges. Each vertex has explicit coordinates, and every edge is a straight line between two vertices that intersects no other edge except at its endpoints.
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Practice › Codeforces Solutions › Codeforces Round 138 (Div. 1) ›

CF 223D - Spider

We are asked to find the shortest path a spider can take on a simple polygon from one vertex to another. The polygon can be concave, but it is guaranteed to have no self-intersections, and its vertices are given in counter-clockwise order.
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Practice › Codeforces Solutions › Codeforces Round 138 (Div. 1) ›

CF 223A - Bracket Sequence

We are given a string consisting only of four bracket characters: (, ), [ and ]. The string is not necessarily balanced. Among all substrings of this string, we need to find one that forms a correct bracket sequence.
codeforces competitive-programming data-structures expression-parsing implementation Jun 4, 2026