balance parentheses

Parens.java

import java.util.*;

public class Test
{

	static String balance(String input) {
		int count = 0;
		StringBuilder sb = new StringBuilder();
		for (char c : input.toCharArray()) {
			if (c == '(') {
				++count;
				sb.append(c);
			} else if (c == ')') {
				if (count - 1 >= 0) {
					--count;
					sb.append(c);
				}
			} else {
				sb.append(c);
			}
		}
		while (count > 0) {
			sb.append(')');
			--count;
		}
		return sb.toString();
	}

	static void test(String in) {
		System.out.print(in + " => ");
		System.out.println(balance(in));
	}

	public static void main(String[] args) {
		test("()()()");
		test("(()()");
		test(")()()");
		test("((()))");
		test("((())");
		test("(()))");
	}
}