Added year directories for advent of code

advent_of_code/2021/d4/main.cpp

@@ -0,0 +1,185 @@
+#include <bits/stdc++.h>
+
+using namespace std;
+
+string FILE_NAME = "4.txt";
+
+struct Card {
+    map<int, pair<int, int>> numbers = {};
+    array<array<bool, 5>, 5> opens;
+
+    Card(){
+        for(int x = 0; x < 5; ++x){
+            opens[x].fill(true);
+        }
+    }
+
+    bool check(pair<int, int> coords){
+        bool x_result = true, y_result = true;
+
+        for(int x = 0; x < 5; ++x){
+            if(opens[x][coords.second]){
+                x_result = false;
+                break;
+            }
+        }
+
+        for(int y = 0; y < 5; ++y){
+            if(opens[coords.first][y]){
+                y_result = false;
+                break;
+            }
+        }
+
+        return x_result || y_result;
+    }
+
+    void insert(int n, pair<int, int> coords){
+        numbers[n] = coords;
+    }
+
+    int score(){
+        int result = 0;
+
+        for(auto n : numbers){
+            auto coords = n.second;
+
+            if(opens[coords.first][coords.second]){
+                result += n.first;
+            }
+        }
+
+        return result;
+    }
+
+    bool call(int n){
+        bool result = false;
+
+        if(numbers.find(n) != numbers.end()){
+            auto coords = numbers[n];
+            opens[coords.first][coords.second] = false;
+
+            result = check(coords);
+        }
+
+        return result;
+    }
+};
+
+vector<int> string_to_int_vector(const string& s){
+    vector<int> result;
+    int carry = 0;
+
+    for(auto c : s){
+        if(c >= 48 && c <= 57){
+            carry *= 10;
+            carry += c - 48;
+        } else{
+            result.push_back(carry);
+            carry = 0;
+        }
+    }
+    result.push_back(carry);
+
+    return result;
+}
+
+int main(){
+    ios::sync_with_stdio(0);
+    cin.tie(0);
+
+    ifstream file_stream;
+    file_stream.open(FILE_NAME);
+
+    if(!file_stream.is_open()){
+        cerr << "File " << FILE_NAME << " not opened correctly\n";
+        return 0;
+    }
+
+    // the first line will always be the sequence of bingo calls
+    string line_1;
+    getline(file_stream, line_1);
+    
+    auto calls = string_to_int_vector(line_1);
+
+    // The second line will always be empty and not parsed or whatever
+    getline(file_stream, line_1);
+
+    vector<Card> bingo_cards;
+    string cur_line;
+
+    while(getline(file_stream, cur_line)){
+        Card card;
+
+        for(int i = 0; i < 5; ++i){
+            istringstream ss(cur_line);
+
+            for(int j = 0; j < 5; ++j){
+                int a;
+                ss >> a;
+
+                card.insert(a, {i, j});
+            }
+
+            getline(file_stream, cur_line);
+        }
+
+        bingo_cards.push_back(card);
+    }
+
+    bool found_result = false;
+
+    cout << "Best board score:" << endl;
+    for(auto n : calls){
+        for(auto& board: bingo_cards){
+            bool r = board.call(n);
+            if(r){
+                cout << n << " * " << board.score() << " = " << n * board.score() << '\n';
+                found_result = true;
+                break;
+            }
+        }
+        if(found_result) break;
+    }
+
+    // Now for part 2, find the worst board. So we go through all boards and see when they finish
+    // Reset all boards first
+    // Then go through all boards and do all calls on them and keep track of the #numbers needed
+
+    int worst_board = 0, calls_needed_worst_board = 0, current_board = 0;
+
+    for(auto& b : bingo_cards){
+        for(int y = 0; y < 5; ++y){
+            b.opens[y].fill(true);
+        }
+
+        int calls_needed = 0;
+
+        for(auto c : calls){
+            bool call_result = b.call(c);
+
+            if(call_result){
+                if(calls_needed_worst_board < calls_needed){
+                    worst_board = current_board;
+                    calls_needed_worst_board = calls_needed;
+                }
+
+                break;
+            }
+            calls_needed++;
+        }
+
+        current_board++;
+    }
+
+    int last_call = calls[calls_needed_worst_board];
+    int worst_board_score = bingo_cards[worst_board].score();
+
+    cout << "Worst board:" << endl;
+    cout << last_call << " * " << worst_board_score << " = " << last_call * worst_board_score << endl;
+
+    cout << flush;
+
+    file_stream.close();
+    return 0;
+}