import java.util.LinkedList;
import java.util.List;
public class FlipGame {
public List generatePossibleNextMoves(String s) {
List result = new LinkedList<>();
for (int i = 0; i < s.length(); ) {
int index = s.indexOf("++", i);
if (index >= i) {
result.add(s.substring(0, index) + "--" + s.substring(index + 2));
i = index + 1;
} else {
break;
}
}
return result;
}
}