public class FlipGameII {
public boolean canWin(String s) {
for (int i = 0; i < s.length(); ) {
int index = s.indexOf("++", i);
if (index >= i) {
String t = s.substring(0, index) + "--" + s.substring(index + 2);
if (!canWin(t)) {
return true;
}
i = index + 1;
} else {
break;
}
}
return false;
}
}