contests/advent_of_code/2021/d10/main.cpp

#include <bits/stdc++.h>

using namespace std;

enum HOOKIES {
    // PARENTHESIS = 3,
    // BRACKET = 57,
    // ACCOLADE = 1197,
    // POINTY_BRACKET = 25137,

    PARENTHESIS = 1,
    BRACKET = 2,
    ACCOLADE = 3,
    POINTY_BRACKET = 4,
};

unsigned int line_score_corrupted(const string& s){
    stack<HOOKIES> chars;
    unsigned int score = 0;

    for(auto c : s){
        if(c == '(' || c == '[' || c == '{' || c == '<'){
            if(c == '('){
                chars.push(PARENTHESIS);
            } else if(c == '['){
                chars.push(BRACKET);
            } else if(c == '{'){
                chars.push(ACCOLADE);
            } else{
                chars.push(POINTY_BRACKET);
            }
        } else if(c == ')' || c == ']' || c == '}' || c == '>'){
            if(chars.empty()){
                score = 0;
                break;
            }

            if(c == ')'){
                if(chars.top() == PARENTHESIS){
                    chars.pop();
                } else{
                    score = PARENTHESIS;
                    break;
                }
            } else if(c == ']'){
                if(chars.top() == BRACKET){
                    chars.pop();
                } else{
                    score = BRACKET;
                    break;
                }
            } else if(c == '}'){
                if(chars.top() == ACCOLADE){
                    chars.pop();
                } else{
                    score = ACCOLADE;
                    break;
                }
            } else{
                if(chars.top() == POINTY_BRACKET){
                    chars.pop();
                } else{
                    score = POINTY_BRACKET;
                    break;
                }
            }
        } else{
            break;
        }
    }

    return score;
}

unsigned int line_score_missing(const string& s){
    stack<HOOKIES> chars;

    bool corrupted = false;

    for(auto c : s){
        if(c == '(' || c == '[' || c == '{' || c == '<'){
            if(c == '('){
                chars.push(PARENTHESIS);
            } else if(c == '['){
                chars.push(BRACKET);
            } else if(c == '{'){
                chars.push(ACCOLADE);
            } else{
                chars.push(POINTY_BRACKET);
            }
        } else if(c == ')' || c == ']' || c == '}' || c == '>'){
            if(chars.empty()){
                corrupted = true;
                break;
            }

            if(c == ')'){
                if(chars.top() == PARENTHESIS){
                    chars.pop();
                } else{
                    corrupted = true;
                    break;
                }
            } else if(c == ']'){
                if(chars.top() == BRACKET){
                    chars.pop();
                } else{
                    corrupted = true;
                    break;
                }
            } else if(c == '}'){
                if(chars.top() == ACCOLADE){
                    chars.pop();
                } else{
                    corrupted = true;
                    break;
                }
            } else{
                if(chars.top() == POINTY_BRACKET){
                    chars.pop();
                } else{
                    corrupted = true;
                    break;
                }
            }
        } else{
            corrupted = true;
            break;
        }
    }

    unsigned int score = 0;
    if(!corrupted){
        while(!chars.empty()){
            auto h = chars.top();
            score = score * 5 + h;
            chars.pop();
        }

        return score;
    }

    return score;
}

int main(){
    ifstream input_file("input.txt");
    string line;

    unsigned int total_score = 0;

    if(input_file.is_open()){
        while(getline(input_file, line)){
            // total_score += line_score_corrupted(line);

            total_score += line_score_missing(line);
        }
    }

    cout << "Total syntax score: " << total_score << endl;

    return 0;
}