feat: add day 4

2023-12-06 23:01:11 +01:00
parent 52784ef81a
commit 14dc992bbc
4 changed files with 344 additions and 2 deletions
--- a/day_4.c
+++ b/day_4.c
@@ -0,0 +1,125 @@
+//
+// Created by lennart on 12/6/23.
+//
+
+#include <ctype.h>
+#include <stdlib.h>
+#include "input_handler.h"
+
+typedef struct {
+    int countWinningNumbers;
+    int winningNumbers[10];
+    int countGivenNumbers;
+    int givenNumbers[25];
+    int copies;
+} Card;
+
+#define LIST_NAME CardList
+#define LIST_PREFIX clist
+#define ELEMENT_TYPE Card
+#include "list.h"
+
+CardList* load_cards(const char *file_name);
+
+int main() {
+    CardList *cards = load_cards("day_4.txt");
+
+    // Part 1 - Iterate over given numbers and linearly check for matches
+    int sum = 0;
+    int sum2 = 0; // Part 2
+    for(int i = 0; i < cards->length; i++) {
+        Card card = cards->data[i];
+        int won = 0;
+
+        for(int j = 0; j < card.countGivenNumbers; j++) {
+            int given = card.givenNumbers[j];
+
+            for(int k = 0; k < card.countWinningNumbers; k++) {
+                if(card.winningNumbers[k] == given) {
+                    won += 1;
+                    continue;
+                }
+            }
+        }
+        sum += (1 << won) >> 1;
+        // Part 2 - Begin (register copies won)
+        sum2 += card.copies;
+        for(int j = 1; j <= won && (i + j) < cards->length; j++) {
+            cards->data[i + j].copies += card.copies;
+        }
+        // Part 2 - End
+    }
+    printf("Result #1: %i\n", sum);
+    printf("Result #2: %i\n", sum2);
+
+    clist_free(cards);
+}
+
+CardList* load_cards(const char *file_name) {
+    FILE *f = fopen(file_name, "r");
+    if(f == NULL) {
+        printf("Error! Missing input file");
+        exit(1);
+    }
+
+    CardList *list = clist_create(16);
+    char* buffer = NULL;
+    int bufferLen = 0;
+
+    while(!feof(f)) {
+        char *line = read_line(f, &buffer, &bufferLen);
+        if(strlen(line) < strlen("Game 1: ")) {
+            continue;
+        }
+
+        line = &line[strlen("Game ")];
+        while(*line == ' ') line++;
+        int gameId = (int) strtol(line, &line, 10);
+
+        Card card;
+        card.countWinningNumbers = 0;
+        card.countGivenNumbers = 0;
+        card.copies = 1;
+
+        // Find the winning numbers
+        line += 2;
+        while(*line != '|') {
+            if(*line == 0) {
+                printf("Error! Unexpected end of line: %s", buffer);
+                exit(1);
+            }
+            if(!isdigit(*line)) {
+                line++;
+                continue;
+            }
+            if(card.countWinningNumbers >= 10) {
+                printf("Error! Given numbers out of bounds in: %s", buffer);
+                exit(1);
+            }
+
+            int num = (int) strtol(line, &line, 10);
+            card.winningNumbers[card.countWinningNumbers++] = num;
+        }
+
+        // Find the given numbers
+        line += 2;
+        while(*line != 0) {
+            if(card.countGivenNumbers >= 25) {
+                printf("Error! Given numbers out of bounds in: %s", buffer);
+                exit(1);
+            }
+            if(!isdigit(*line)) {
+                line++;
+                continue;
+            }
+
+            int num = (int) strtol(line, &line, 10);
+            card.givenNumbers[card.countGivenNumbers++] = num;
+        }
+
+        clist_add(list, card);
+    }
+
+    free(buffer);
+    return list;
+}