1 files changed, 147 insertions, 0 deletions
diff --git a/Advent-of-Code-2022/aoc-5/main.c b/Advent-of-Code-2022/aoc-5/main.c
new file mode 100644
index 0000000..409cf6b
--- /dev/null
+++ b/Advent-of-Code-2022/aoc-5/main.c
@@ -0,0 +1,147 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#if 0
+  #define transfer transfer_part1
+#else
+  #define transfer transfer_part2
+#endif
+
+#if 0
+  #define FILENAME "sample.txt"
+  #define COLUMNS 3
+#else
+  #define FILENAME "input.txt"
+  #define COLUMNS 9
+#endif
+
+#define STRINT(d) atoi(strtok(NULL, d)); strtok(NULL, d);
+
+typedef struct crate crate;
+crate *create_crate(char data);
+void push(crate *c, int i);
+crate *add(crate *c, crate *last, int i);
+crate *pop(int i);
+void transfer_part1(int from, int to, int n);
+void transfer_part2(int from, int to, int n);
+void free_crates(crate *c);
+void print_crate(char *format, crate *c);
+
+crate *top[COLUMNS+1] = {0};
+
+void parse()
+{
+    FILE *fp = fopen(FILENAME, "r");
+	if(!fp) {
+        fprintf(stderr, "ERROR: Could not open file: %s\n", FILENAME);
+        exit(1);
+    }
+
+    char line[256] = {0};
+    crate *last[COLUMNS] = {0};
+    while(fgets(line, sizeof(line), fp) != NULL && line[0] != '\n')
+    {
+        for(int i = 0; i < COLUMNS; i++) {
+            char ch = line[(i*4)+1];
+            if(ch >= 65 && ch <= 90) {
+                last[i] = add(create_crate(ch), last[i], i);
+            }
+        }
+    }
+
+    while(fgets(line, sizeof(line), fp) != NULL)
+    {
+        strtok(line, " ");
+        int n = STRINT(" ");
+        int from = STRINT(" ");
+        int to   = STRINT(" ");
+
+        transfer(from-1, to-1, n);
+    }
+
+    fclose(fp);
+}
+
+int main(void)
+{
+    parse();
+    for(int i = 0; i < COLUMNS; i++) {
+        print_crate("%c", top[i]);
+        free_crates(top[i]);
+    }
+    puts("");
+    return 0;
+}
+
+
+
+struct crate {
+    char data;
+    struct crate *prev;
+};
+
+crate *create_crate(char data)
+{
+    crate *c = malloc(sizeof(crate));
+    c->data = data;
+    c->prev = NULL;
+    return c;
+}
+
+void push(crate *c, int i)
+{
+    c->prev = top[i];
+    top[i] = c;
+}
+
+crate *add(crate *c, crate *last, int i)
+{
+    if(last == NULL) {
+        push(c, i);
+        return c;
+    }
+
+    last->prev = c;
+    return c;
+}
+
+crate *pop(int i)
+{
+    if(top[i] == NULL) {
+        fprintf(stderr, "ERROR: Column %d is empty, can't pop\n", i);
+        exit(1);
+    }
+
+    crate *c = top[i];
+    top[i] = c->prev;
+    return c;
+}
+
+void transfer_part1(int from, int to, int n)
+{
+    for(int i = 0; i < n; i++)
+        push(pop(from), to);
+}
+
+void transfer_part2(int from, int to, int n)
+{
+    for(int i = 0; i < n; i++)
+        push(pop(from), COLUMNS);
+    for(int i = 0; i < n; i++)
+        push(pop(COLUMNS), to);
+}
+
+void free_crates(crate *c)
+{
+    if(c == NULL) return;
+    crate *prev = c->prev;
+    free(c);
+    free_crates(prev);
+}
+
+void print_crate(char *format, crate *c)
+{
+    if(c == NULL) return;
+    printf(format, c->data);
+}