Solution: Flip Game
Explore how to solve the Flip Game problem using backtracking principles by identifying every valid move of flipping consecutive plus signs into minuses. Understand how to systematically generate all next valid states and analyze the time and space complexities associated with this approach. This lesson helps you practice implementing enumerative backtracking without complex undo steps, building confidence in handling combinatorial string manipulation problems in coding interviews.
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Statement
You are playing a Flip Game with a friend.
You are given a string currentState consisting only of the characters '+' and '-'. Players take turns flipping two consecutive "++" into "--". The game ends when a player cannot make a move, at which point the other player wins.
Return all possible states of currentState after performing exactly one valid move. The answer may be returned in any order. If no valid move exists, return an empty list.
Constraints:
currentState.lengthcurrentState[i]is either'+'or'-'
Solution
The main idea is to generate all possible valid next moves by ...