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 [].
public class Solution {
public List<String> generatePossibleNextMoves(String s) {
List<String> res = new ArrayList<String>();
if (s==null || s.length()<=1) return res;
for (int i=0; i<s.length()-1; i++) {
if (s.charAt(i)==‘+‘ &&s.charAt(i+1)==‘+‘)
res.add(process(s, i));
}
return res;
}
public String process(String s, int i) {
StringBuffer result = new StringBuffer();
result.append(s.substring(0, i));
result.append("--");
result.append(s.substring(i+2));
return result.toString();
}
}
原文：http://www.cnblogs.com/apanda009/p/7395270.html