LeetCode 293: Flip Game

Explanation

This problem asks to determine all possible states after flipping a "++" to "--" in a given string. We can solve this by iterating through the string and checking each occurrence of "++". If found, we can flip it to "--" and add the resulting string to our list of solutions.

• Initialize an empty list to store solutions.
• Iterate through the string, checking for occurrences of "++".
• If found, create a new string by flipping the "++" to "--" and add it to the list of solutions.
• Return the list of solutions.

Time Complexity: O(n) where n is the length of the input string. Space Complexity: O(n) considering the space required to store the resulting solutions.

import java.util.ArrayList;
import java.util.List;

class Solution {
    public List<String> generatePossibleNextMoves(String s) {
        List<String> result = new ArrayList<>();
        
        for (int i = 0; i < s.length() - 1; i++) {
            if (s.charAt(i) == '+' && s.charAt(i + 1) == '+') {
                StringBuilder sb = new StringBuilder(s);
                sb.setCharAt(i, '-');
                sb.setCharAt(i + 1, '-');
                result.add(sb.toString());
            }
        }
        
        return result;
    }
}