LeetCode 301: Remove Invalid Parenthesis

Note:

It could be other chars in the String. Do not count as invalid parenthesis.

Second try:

1. Count j until i. not exceed i.

2. Return after remove char since it will duplicate.

class Solution {
public List<String> removeInvalidParentheses(String s) {
List<String> result = new ArrayList<>();
remove(s, result, 0, 0, new char[]{'(', ')'});
return result;
}

private void remove(String input, List<String> result, int lastI, int lastJ, char[] pattern) {
for (int count = 0, i = lastI; i < input.length(); i++) {
if (input.charAt(i) == pattern[0]) {
count++;
}
if (input.charAt(i) == pattern[1]) {
count--;
}

if (count >= 0) {
continue;
}

for (int j = lastJ; j <= i; j++) {
if (input.charAt(j) == pattern[1] && (j == lastJ || input.charAt(j - 1) != pattern[1])) {
remove(input.substring(0, j) + input.substring(j + 1), result, i, j, pattern);
}
}
return;
}

String reversed = new StringBuilder(input).reverse().toString();
if (pattern[0] == '(') {
remove(reversed, result, 0, 0, new char[]{')', '('});
} else {
result.add(reversed);
}
}
}