Codeforces Round 664 (Div. 1)

Solutions for Codeforces Round 664 (Div. 1) (contest 1394). 1/5 problems verified against sample I/O. Difficulty range: 1800-3500.

5 items

Codeforces Round 664 (Div. 1)

Type: Div. 1 | Problems: 5 | Verified: 1/5 | Rating range: 1800-3500 | Time: 20m 59s

Problem Name Rating Tags Solve Time Verified
A Boboniu Chats with Du 1800 dp, greedy, sortings 5m 19s ✗
B Boboniu Walks on Graph 2300 brute-force, dfs-and-similar, graphs 8m 53s ✗
C Boboniu and String 2600 binary-search, geometry, ternary-search 2m 5s ✓
D Boboniu and Jianghu 2800 dp, greedy, sortings 2m 24s ✗
E Boboniu and Banknote Collection 3500 strings 2m 18s ✗
Practice › Codeforces Solutions › Codeforces Round 664 (Div. 1) ›

CF 1394B - Boboniu Walks on Graph

Ah, now the bug is about the order in which the pairs are generated. The input is: and the expected output is: The previous code produced the pairs row-major from (1,1) to (n,m), which is why it printed: That is lexicographical order by row then column, but the problem wants a…
codeforces competitive-programming brute-force dfs-and-similar graphs hashing Jun 11, 2026
Practice › Codeforces Solutions › Codeforces Round 664 (Div. 1) ›

CF 1394E - Boboniu and Banknote Collection

We are given a sequence that grows one element at a time, and after each prefix we want to know how “deeply foldable” it is under a very specific rule. A folding is represented by assigning each position a direction, either +1 or -1.
codeforces competitive-programming strings Jun 11, 2026
Practice › Codeforces Solutions › Codeforces Round 664 (Div. 1) ›

CF 1394A - Boboniu Chats with Du

We are given a sequence of “fun values” representing how entertaining Du’s messages are on each day. We are allowed to rearrange these values in any order before the process starts. After fixing an order, the days proceed from left to right.
codeforces competitive-programming dp greedy sortings two-pointers Jun 11, 2026
Practice › Codeforces Solutions › Codeforces Round 664 (Div. 1) ›

CF 1394D - Boboniu and Jianghu

We are given a tree of n mountains, connected by n-1 roads so that every mountain is reachable from any other. Each mountain has a height hi and a tiredness ti.
codeforces competitive-programming dp greedy sortings trees Jun 11, 2026
Practice › Codeforces Solutions › Codeforces Round 664 (Div. 1) ›

CF 1394C - Boboniu and String

We are given several strings composed only of two characters, which we can think of as two symbols, say B and N. The task is to choose another string t over the same alphabet such that all given strings can be transformed into something “equivalent” to t under a specific…
codeforces competitive-programming binary-search geometry ternary-search Jun 11, 2026