Minimum Bracket Addition - Amazon Top Interview Questions


Problem Statement :


Given a string s containing brackets ( and ), return the minimum number of brackets that can be inserted so that the brackets are balanced.

Constraints

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

Example 1

Input

s = ")))(("


Output

5

Explanation

We can insert ((( to the front and )) to the end


Solution :



title-img 




                        Solution in C++ :

int solve(string s) {
    int left = 0;
    int stack = 0;

    for (auto c : s) {
        if (!stack && c == ')')
            ++left;
        else if (c == '(')
            ++stack;
        else
            --stack;
    }
    return left + stack;
}
                    


                        Solution in Java :

import java.util.*;

class Solution {
    public int solve(String s) {
        int open = 0;
        int count = 0;

        for (char c : s.toCharArray()) {
            if (c == '(')
                open++;
            else {
                if (open == 0)
                    count++;
                else
                    open--;
            }
        }
        return count + open;
    }
}
                    


                        Solution in Python : 
                            
class Solution:
    def solve(self, s):
        stack = []
        res = 0

        for b in s:
            if b == ")":
                if len(stack) > 0 and stack[-1] == "(":
                    stack.pop()
                else:
                    stack.append(")")
            else:
                stack.append("(")

        return len(stack)


View More Similar Problems

Jenny's Subtrees

Jenny loves experimenting with trees. Her favorite tree has n nodes connected by n - 1 edges, and each edge is ` unit in length. She wants to cut a subtree (i.e., a connected part of the original tree) of radius r from this tree by performing the following two steps: 1. Choose a node, x , from the tree. 2. Cut a subtree consisting of all nodes which are not further than r units from node x .

View Solution →

Tree Coordinates

We consider metric space to be a pair, , where is a set and such that the following conditions hold: where is the distance between points and . Let's define the product of two metric spaces, , to be such that: , where , . So, it follows logically that is also a metric space. We then define squared metric space, , to be the product of a metric space multiplied with itself: . For

View Solution →

Array Pairs

Consider an array of n integers, A = [ a1, a2, . . . . an] . Find and print the total number of (i , j) pairs such that ai * aj <= max(ai, ai+1, . . . aj) where i < j. Input Format The first line contains an integer, n , denoting the number of elements in the array. The second line consists of n space-separated integers describing the respective values of a1, a2 , . . . an .

View Solution →

Self Balancing Tree

An AVL tree (Georgy Adelson-Velsky and Landis' tree, named after the inventors) is a self-balancing binary search tree. In an AVL tree, the heights of the two child subtrees of any node differ by at most one; if at any time they differ by more than one, rebalancing is done to restore this property. We define balance factor for each node as : balanceFactor = height(left subtree) - height(righ

View Solution →

Array and simple queries

Given two numbers N and M. N indicates the number of elements in the array A[](1-indexed) and M indicates number of queries. You need to perform two types of queries on the array A[] . You are given queries. Queries can be of two types, type 1 and type 2. Type 1 queries are represented as 1 i j : Modify the given array by removing elements from i to j and adding them to the front. Ty

View Solution →

Median Updates

The median M of numbers is defined as the middle number after sorting them in order if M is odd. Or it is the average of the middle two numbers if M is even. You start with an empty number list. Then, you can add numbers to the list, or remove existing numbers from it. After each add or remove operation, output the median. Input: The first line is an integer, N , that indicates the number o

View Solution →