CodingMediumcod-g800

Subject RecursionLevel Mid–Senior~30 minCommon in Algorithms & data structures interviewsIndustries Software development, Computer games

Question

Two players alternate turns on a string of '+' and '-' characters. On a move a player flips two consecutive '++' into '--'. A player who cannot move loses. Given the starting string `s`, return true if the player to move first can guarantee a win with optimal play. 1 <= len(s) <= 18.

Implement

can_win(s: str) → bool

Examples

in["++++"]outtrue

What a strong answer looks like

State your approach and its time/space complexity out loud before you optimize. Handle the edge cases (empty input, duplicates, overflow), and say why you chose this over the brute force. Green tests are the floor, not the grade.

Learn the concepts

Vibe coding: describe the solution in plain language (or narrate it) and the coach grades your approach. Generating runnable code from your description is coming next.

Run or narrate your approach, then ask the coach.