LeetCode － Flip Game
Tags: Algorithm, LeetCodeYou 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:
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[ "--++", "+--+", "++--" ] |
If there is no valid move, return an empty list [].
Analysis
We traverse the string, if there are two consecutive
+s, we set them into --, and add the new string to the list. Then we reset them back to ++ for the next step. Java Solution
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class FlipGame { public List<String> flip(String s){ List<String> res = new ArrayList<>(); char[] ary = s.toCharArray(); for(int i = 0; i < ary.length - 1; i++) { if(ary[i] == '+' && ary[i + 1] == '+') { ary[i] = '-'; ary[i + 1] = '-'; res.add(new String(ary)); ary[i] = '+'; ary[i + 1] = '+'; } } return res; } } |
The following up of this problem is flip game II.
