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 :
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)
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