Add solution for day 5, improve older solutions

Author: JohnnyJayJay

Day-01/c/JohnnyJayJay/Day01.c

@@ -1,5 +1,4 @@
-/* compile from project root using 
-   cc -Wall -g shared/JohnnyJayJay/aoc.c Day-01/c/JohnnyJayJay/Day01.c -o day01 */
+// Read my README in shared/JohnnyJayJay
 
 #include <stdio.h>
 #include <stdlib.h>

Day-02/c/JohnnyJayJay/Day02.c

@@ -30,11 +30,11 @@ int main(int argc, char** argv) {
     int valid_passwords1 = 0;
     int valid_passwords2 = 0;
     for (int i = 0; i < lines; i++) {
-        db_entry entry = entries[i];
-        char* pw = entry.password;
-        char c = entry.c;
-        int min = entry.min;
-        int max = entry.max;
+        db_entry* entry = &entries[i];
+        char* pw = entry->password;
+        char c = entry->c;
+        int min = entry->min;
+        int max = entry->max;
         int count = charcount(pw, c, 0, strlen(pw));
         if (count >= min && count <= max) {
             valid_passwords1++;

Day-05/c/JohnnyJayJay/Day05.c

@@ -0,0 +1,60 @@
+// Read my README in shared/JohnnyJayJay
+
+#include <stdio.h>
+#include <stdlib.h>
+#include "../../../shared/JohnnyJayJay/aoc.h"
+
+int find_value(char* desc, int length, char lower, char upper) {
+    int min = 0;
+    int delta = 1 << length;
+    for (int i = 0; i < length; i++) {
+        delta /= 2;
+        if (desc[i] == upper) {
+            min += delta;
+        }
+    }
+    return min;
+}
+
+int intcmp(const void* one, const void* two) {
+    int a = *((int*) one);
+    int b = *((int*) two);
+    if (a == b) {
+        return 0;
+    } else if (a < b) {
+        return -1;
+    } else {
+        return 1;
+    }
+}
+
+int main(int argc, char** argv) {
+    FILE* file = fopen(argv[1], "r");
+    int lines = count_lines(file);
+    char row_desc[8];
+    char column_desc[4];
+    int* passes = malloc(sizeof(int) * lines); 
+    for (int i = 0; i < lines; i++) {
+        fscanf(file, "%7s%3s", row_desc, column_desc);
+        int row = find_value(row_desc, 7, 'F', 'B');
+        int column = find_value(column_desc, 3, 'L', 'R');
+        passes[i] = row * 8 + column;
+    }
+    qsort(passes, lines, sizeof(int), &intcmp);
+    int max_seat_id = passes[lines - 1];
+    printf("Highest seat id: %d\n", max_seat_id);
+    int own_seat_id = 0;
+    for (int i = 0; i < lines - 1; i++) {
+        int first = passes[i];
+        int second = passes[i + 1];
+        if (abs(first - second) == 2) {
+            own_seat_id = first + 1;
+            break;
+        }
+    }
+    printf("%d\n", lines);
+    printf("Own seat id: %d\n", own_seat_id);
+}
+        
+        
+        

shared/JohnnyJayJay/aoc.c

@@ -3,13 +3,17 @@
 
 int count_lines(FILE* file) {
     long pos = ftell(file);
-    int lines = 1;
+    int lines = 0;
     int c;
     while ((c = fgetc(file)) != EOF) {
         if (c == '\n') {
             lines++;
         }
     }
+    fseek(file, -1, SEEK_CUR);
+    if (fgetc(file) != '\n') {
+        lines++;
+    }
     fseek(file, pos, SEEK_SET);
     return lines;
 }