Codeforces_CompCodes/BracketSequence.cpp at main · masterishaan19/Codeforces_CompCodes · GitHub

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#include <bits/stdc++.h>
using namespace std;
bool areParanthesisBalanced(string expr)
{
    stack<char> s;
    char x;
    for (int i = 0; i < expr.length(); i++)
    {
        if (expr[i] == '(' || expr[i] == '[' || expr[i] == '{')
        {
            s.push(expr[i]);
            continue;
        }
        if (s.empty())
            return false;
        switch (expr[i])
        {
        case ')':
            x = s.top();
            s.pop();
            if (x == '{' || x == '[')
                return false;
            break;
        case '}':
            x = s.top();
            s.pop();
            if (x == '(' || x == '[')
                return false;
            break;

        case ']':
            x = s.top();
            s.pop();
            if (x == '(' || x == '{')
                return false;
            break;
        }
    }
    return (s.empty());
}

int main()
{
    string str;
    cin >> str;
    if (areParanthesisBalanced(str))
        cout << "Valid Bracket Seq.";
    else
        cout << "Invalid Bracket Seq.";
    return 0;
}