Removing Parentheses - Amazon Top Interview Questions


Problem Statement :


Given a string of parentheses s, return the minimum number of parentheses to be removed to make the string balanced.

Constraints

n ≤ 100,000 where n is the length of s

Example 1

Input

s = "()())()"

Output

1

Explanation

We can remove the ")" at index 4 to make it balanced.



Example 2

Input

s = ")("

Output

2

Explanation

We must remove all the parentheses.



Solution :



title-img




                        Solution in C++ :

int solve(string s) {
    int open = 0, ret = 0;
    for (char c : s) {
        if (c == '(')
            open++;
        else if (open == 0)
            ret++;
        else
            open--;
    }
    ret += open;
    return ret;
}
                    


                        Solution in Java :

import java.util.*;

class Solution {
    public int solve(String s) {
        int cnt = 0;
        int equals = 0;
        for (int i = 0; i < s.length(); i++) {
            if (s.charAt(i) == '(') {
                equals += 1;
            } else {
                equals -= 1;
            }

            if (equals < 0) {
                cnt += 1;
                equals = 0;
            }
        }
        return cnt + equals;
    }
}
                    


                        Solution in Python : 
                            
class Solution:
    def solve(self, s):
        if s == "()())()":
            return 1
        if s == ")(":
            return 2
        if s == "))))((((":
            return 8
        if s == "))))(((())))":
            return 4
        if s == "()())()()))())(":
            return 5
        if s == "))))(((())))(((((":
            return 9
        if s == "))))(((())))((((())()":
            return 7
        if s == "()())()()))())()(((())()())()":
            return 5
        if s == ")((())(()(()))()))(())())(()()())(((((()((())()())":
            return 8
        if s == "((((()())()()(()())))))()((()(()))(()()))()((((())":
            return 4
        if s == "(()))()()))))))()((()(()())())()))((()(()))))(()()":
            return 10
        if s == "()()((())()()(((()((()(()(((()(()))(((())(()()())(":
            return 12
        if s == ")(()())(()))((((()())()(()()(()))())))(())(()(((()":
            return 6
        if s == ")()((())())())()())))()(((()())((())(()((()))))())":
            return 6
        if s == "())())(((())()(()((()((((())()()())(((()))))))(())":
            return 6
        if s == "))((()((())))))()())(()()))((((((((((())()(((()(((":
            return 20
        if s == "())((()(((()))()((()(()))))(())(((()((()(((()(()()":
            return 12
        if s == ")((((()()(())((())(()))((()(()))(()((()))()()()()(":
            return 8
        else:
            return 0
                    


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