From 6b979797521067f7f6aaf788638c70127a07d208 Mon Sep 17 00:00:00 2001
From: Bill Rossi <bassguitarbill@gmail.com>
Date: Sat, 21 Dec 2024 07:05:08 -0500
Subject: [PATCH] Agh

---
 c/2024/17/chronospatial_computer.c | 145 +++++++++++++++++++++++++++++
 1 file changed, 145 insertions(+)
 create mode 100644 c/2024/17/chronospatial_computer.c

diff --git a/c/2024/17/chronospatial_computer.c b/c/2024/17/chronospatial_computer.c
new file mode 100644
index 0000000..dceb005
--- /dev/null
+++ b/c/2024/17/chronospatial_computer.c
@@ -0,0 +1,145 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <limits.h>
+
+#include "../../lib/aoc.h"
+
+#define PROGRAM_LENGTH 16
+
+typedef struct Computer {
+  long a;
+  long b;
+  long c;
+  long program[PROGRAM_LENGTH];
+  int pc;
+  long output[1000];
+  int output_count;
+} Computer;
+
+long combo(Computer *c, int operand) {
+  switch (operand) {
+  case 0:
+  case 1:
+  case 2:
+  case 3:
+    return operand;
+  case 4:
+    return c->a;
+  case 5:
+    return c->b;
+  case 6:
+    return c->c;
+  default:
+    printf("Invalid operand %d detected\n", operand);
+    exit(1);
+  }
+}
+
+void step(Computer *c) {
+  int instruction = c->program[c->pc++];
+  int operand = c->program[c->pc++];
+  // printf("%d|%d\n", instruction, operand);
+  // printf("a: %d, b: %d, c: %d, pc: %d\n", c->a, c->b, c->c, c->pc);
+  switch(instruction) {
+  case 0:
+    // printf("0: a = %d / %d = %d\n", c->a, 1<<combo(c, operand), c->a / (1<<combo(c, operand)));
+    c->a = c->a / (1 << combo(c, operand));
+    break;
+  case 1:
+    // printf("1: b = %d ^ %d = %d\n", c->b, operand, c->b ^ operand);
+    c->b = operand ^ c->b;
+    break;
+  case 2:
+    // printf("2: b = %d % 8 = %d\n", combo(c, operand), combo(c, operand) % 8);
+    c->b = combo(c, operand) % 8;
+    break;
+  case 3:
+    // printf("3: if %d then jump to %d\n", c->a, operand);
+    if (c->a) c->pc = operand;
+    break;
+  case 4:
+    // printf("4: b = %d ^ %d = %d\n", c->b, c->c, c->b ^ c->c);
+    c->b = c->b ^ c->c;
+    break;
+  case 5:
+    // printf("5: print %d\n", combo(c, operand) % 8);
+    c->output[c->output_count++] = combo(c, operand) % 8;
+    break;
+  case 6:
+    // printf("6: b = %d / %d = %d\n", c->b, 1<<combo(c, operand), c->b / (1<<combo(c, operand)));
+    c->b = c->a / (1 << combo(c, operand));
+    break;
+  case 7:
+    // printf("7: c = %d / %d = %d\n", c->a, 1<<combo(c, operand), c->a / (1<<combo(c, operand)));
+    c->c = c->a / (1 << combo(c, operand));
+    break;
+  }
+}
+
+bool quine(Computer *c, long a) {
+  if (a % 100000000 == 0) printf("%ld\n", a);
+  c->a = a;
+  c->b = 0;
+  c->c = 0;
+  c->pc = 0;
+  c->output_count = 0;
+  while (c->pc < PROGRAM_LENGTH) {
+    step(c);
+    if (c->output_count == 0) continue;
+    if (c->output[c->output_count - 1] != c->program[c->output_count - 1]) return false;
+  }
+  if (c->output_count != PROGRAM_LENGTH) return false;
+  for (int i = 0; i < c->output_count; c++) {
+    if (c->program[i] != c->output[i]) return false;
+  }
+  return true;
+}
+
+int main() {
+  printf("%s\n", aoc_read_input());
+  Computer c;
+  c.pc = 0;
+
+  sscanf(aoc_read_line(), "Register A: %d", &(c.a));
+  sscanf(aoc_read_line(), "Register B: %d", &(c.b));
+  sscanf(aoc_read_line(), "Register C: %d", &(c.c));
+  aoc_read_line();
+  strtok(aoc_read_line(), " ");
+  for (char *token = strtok(NULL, ","); token != NULL; token = strtok(NULL, ",")) {
+    c.program[c.pc++] = atoi(token);
+  }
+  c.pc = 0;
+  c.output_count = 0;
+
+  while (c.pc < PROGRAM_LENGTH) {
+    printf("a: %d, b: %d, c: %d, pc: %d\n", c.a, c.b, c.c, c.pc);
+    step(&c);
+    // printf("\n");
+  }
+
+  printf("Part 1: %d", c.output[0]);
+  for (int i = 1; i < c.output_count; i++) {
+    printf(",%d", c.output[i]);
+  }
+  printf("\n");
+
+  //long a = 100000000000000;
+  // long a = 8 ** 15;
+  // long a = 2 ** 45;
+  long a = 1l << 45l;
+  for (; a < (1l << 48l); a++) {
+    quine(&c, a);
+    /*printf("%ld: ", a);
+    for (int i = 0; i < c.output_count; i++) {
+      printf("%ld,", c.output[i]);
+    }
+    printf("\n");*/
+  }
+  // while (!quine(&c, a)) a++;
+  printf("Part 2: %ld", a);
+
+  aoc_free();
+  exit(0);
+}