293. Flip Game
Problem:
You are playing the following Flip Game with your friend: Given a string that contains only these two characters: + and -, you and your friend take turns to flip two consecutive "++" into "--". The game ends when a person can no longer make a move and therefore the other person will be the winner.
Write a function to compute all possible states of the string after one valid move.
For example, given s = "++++", after one move, it may become one of the following states:
[ "--++", "+--+", "++--" ] If there is no valid move, return an empty list [].
Solutions:
public class Solution {
public List<String> generatePossibleNextMoves(String s) {
List<String> result = new LinkedList<String>();
StringBuilder sb = new StringBuilder(s);
for (int i = 0; i < s.length() - 1; i ++) {
if (s.charAt(i) == '+' && s.charAt(i + 1) == '+') {
sb.setCharAt(i, '-');
sb.setCharAt(i + 1, '-');
result.add(sb.toString());
sb.setCharAt(i, '+');
sb.setCharAt(i + 1, '+');
}
}
return result;
}
}