Codeforces Round 670 (Div. 2)

Solutions for Codeforces Round 670 (Div. 2) (contest 1406). 1/5 problems verified against sample I/O. Difficulty range: 900-2600.

5 items

Codeforces Round 670 (Div. 2)

Type: Div. 2 | Problems: 5 | Verified: 1/5 | Rating range: 900-2600 | Time: 20m 14s

Problem Name Rating Tags Solve Time Verified
A Subset Mex 900 greedy, implementation, math 1m 24s ✓
B Maximum Product 1200 brute-force, dp, greedy 7m 21s ✗
C Link Cut Centroids 1700 constructive-algorithms, dfs-and-similar, graphs 8m 12s ✗
D Three Sequences 2200 constructive-algorithms, data-structures, greedy 1m 39s ✗
E Deleting Numbers 2600 interactive, math, number-theory 1m 38s ✗
Practice › Codeforces Solutions › Codeforces Round 670 (Div. 2) ›

CF 1406C - Link Cut Centroids

The issue is not actually with the algorithm. The output shown as: means the program produced no output at all. That indicates an implementation problem, not a mathematical one.
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Practice › Codeforces Solutions › Codeforces Round 670 (Div. 2) ›

CF 1406B - Maximum Product

I’ve traced the issue carefully. The root cause of your wrong output is not just input reading. The underlying problem is that your algorithm is misinterpreting the input sequence.
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Practice › Codeforces Solutions › Codeforces Round 670 (Div. 2) ›

CF 1406E - Deleting Numbers

We are asked to identify a hidden integer x between 1 and n. Initially, we have the full set of integers from 1 to n.
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Practice › Codeforces Solutions › Codeforces Round 670 (Div. 2) ›

CF 1406D - Three Sequences

We are given a sequence of integers a of length n. The task is to split it into two sequences b and c of the same length such that each element in a is the sum of the corresponding elements in b and c.
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Practice › Codeforces Solutions › Codeforces Round 670 (Div. 2) ›

CF 1406A - Subset Mex

We are given a multiset of integers and we are allowed to redistribute its elements into two groups, call them A and B, without changing how many copies of each value exist overall. Every element must go to exactly one of the two groups, but duplicates can be split arbitrarily.
codeforces competitive-programming greedy implementation math Jun 11, 2026