🔎🔎 Parenthesis Checker 🔎🔎

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Statement 🚀🚀

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Given an expression (containing Parenthesis) string str . you have to write a program to check whether the pair of brackets are in the correct order or not.

Example : 1 🚀🚀

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Input

• str = "([{}])"

Output

• YES

Explanatation

• ( [ { } ] ) , { closed with } , [ closed with ] and ( closed with ) .

Example : 2 🚀🚀

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Input

• str = "({[}])"

Output

• NO

Explanatation

• Parenthesis are not in order .

💻💻 Before moving on to solution part , try this this question through following link : Problem link 🚀🚀

Logic 🚀🚀

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• create an empty stack s .

• Traverse the string str

  • if you found any open brackets push character into the stack.

  • else

    • if( stack is empty ) : return false.
    • if top of stack element do not match with their corresponding closed bracket then return false.
    • if top of stack element matches with their corresponding closed bracket then pop that top element. and continue to next iteration.

#include <bits/stdc++.h>
using namespace std;
bool check(char a, char b)
{
    return ((a == '(' and b == ')') or
            (a == '{' and b == '}') or
            (a == '[' and b == ']'));
}
bool solve(string str)
{
    stack<char> s;
    for (int i = 0; i < str.length(); i++)
    {
        if (str[i] == '(' or str[i] == '[' or str[i] == '{')
        {
            s.push(str[i]);
        }
        else
        {
            if (s.empty() == true)
            {
                return false;
            }
            if (check(s.top(), str[i]))
            {
                s.pop();
            }
            else
            {
                return false;
            }
        }
    }
    return (s.empty() == true);
}
int main()
{
    string s;
    cin >> s;
    if (solve(s))
        cout << "YES" << endl;
    else
        cout << "NO" << endl;
    return 0;
}

Complexity Analysis