BalancingParantheses.cpp

/*
Input Format. Input contains one string 𝑆 which consists of big and small latin letters, digits, punctuation
marks and brackets from the set []{}().

Constraints. The length of 𝑆 is at least 1 and atmost 10^5.

Output Format. If the code in 𝑆 uses brackets correctly, output “Success" (without the quotes). Otherwise,
output the 1-based index of the first unmatched closing bracket, and if there are no unmatched closing
brackets, output the 1-based index of the first unmatched opening bracket.
*/
#include<bits/stdc++.h>
using namespace std;
struct Parantheses{
	Parantheses(int type, int pos):
        type(type),
        pos(pos){}
    	bool ArePair(char bracket){
        if (type == '[' && bracket == ']') return true;
        if (type == '{' && bracket == '}') return true;
        if (type == '(' && bracket == ')') return true;
        return false;
    }
    char type;
    int pos;
};
int main(){
    string str;
    cin>>str;
    int flag = -1;

    stack <Parantheses > S;
    if (str.length()<=1) {
        cout<<"1";
        return 0;
    }
    for (int pos=0;pos<str.length(); pos++){
        char next = str[pos];

        if (next == '(' || next == '[' || next == '{'){
            S.push(Parantheses(next,pos));
        }
        if (next == ')' || next == ']' || next == '}'){
            if (!S.empty() && S.top().ArePair(next)){
                S.pop();
            }
			else{ 
                cout<<pos+1;
                return 0;
            }
        }
    }
   if (S.empty() && flag == -1){
		cout<<"Success";
	}
	else if (flag == -1){
        cout<<S.top().pos+1;
    }
	else{
        cout<<flag + 1;
    }
    return 0;
}