From 413d4d4631bef22b040b241fc8cc19ed0af7270f Mon Sep 17 00:00:00 2001
From: Bill Rossi <bassguitarbill@gmail.com>
Date: Wed, 4 Dec 2024 05:51:19 -0500
Subject: [PATCH] c 2024 day 4 part 1

---
 c/2024/4/ceres_search.c | 111 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 111 insertions(+)
 create mode 100644 c/2024/4/ceres_search.c

diff --git a/c/2024/4/ceres_search.c b/c/2024/4/ceres_search.c
new file mode 100644
index 0000000..4561463
--- /dev/null
+++ b/c/2024/4/ceres_search.c
@@ -0,0 +1,111 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+
+#include "../../lib/aoc.h"
+
+char *target_string = "XMAS";
+#define TARGET_STRING_LENGTH 4
+
+typedef struct Puzzle {
+  char *text;
+  int width;
+  int height;
+} Puzzle;
+
+char puzzle_char_at(Puzzle *puzzle, int row, int column) {
+  return puzzle->text[column + (puzzle->width * row)];
+}
+
+bool puzzle_inbounds(Puzzle *puzzle, int row, int column) {
+  return row < puzzle->height && row >= 0 && column >= 0 && column < puzzle->width;
+}
+
+int target_string_count(Puzzle *puzzle, int index) {
+  if (puzzle->text[index] != target_string[0]) return 0;
+  int count = 0;
+  int row = index / puzzle->width;
+  int column = index % puzzle->width;
+
+  // right
+  for (int i = 1; i < TARGET_STRING_LENGTH; i++) {
+    if (!puzzle_inbounds(puzzle, row, column + i)) break;
+    if (puzzle_char_at(puzzle, row, column + i) != target_string[i]) break;
+    if (i == TARGET_STRING_LENGTH - 1) count += 1;
+  }
+
+  // down right
+  for (int i = 1; i < TARGET_STRING_LENGTH; i++) {
+    if (!puzzle_inbounds(puzzle, row + i, column + i)) break;
+    if (puzzle_char_at(puzzle, row + i, column + i) != target_string[i]) break;
+    if (i == TARGET_STRING_LENGTH - 1) count += 1;
+  }
+
+  // down
+  for (int i = 1; i < TARGET_STRING_LENGTH; i++) {
+    if (!puzzle_inbounds(puzzle, row + i, column)) break;
+    if (puzzle_char_at(puzzle, row + i, column) != target_string[i]) break;
+    if (i == TARGET_STRING_LENGTH - 1) count += 1;
+  }
+
+  // down left
+  for (int i = 1; i < TARGET_STRING_LENGTH; i++) {
+    if (!puzzle_inbounds(puzzle, row + i, column - i)) break;
+    if (puzzle_char_at(puzzle, row + i, column - i) != target_string[i]) break;
+    if (i == TARGET_STRING_LENGTH - 1) count += 1;
+  }
+
+  // left
+  for (int i = 1; i < TARGET_STRING_LENGTH; i++) {
+    if (!puzzle_inbounds(puzzle, row, column - i)) break;
+    if (puzzle_char_at(puzzle, row, column - i) != target_string[i]) break;
+    if (i == TARGET_STRING_LENGTH - 1) count += 1;
+  }
+
+  // up left
+  for (int i = 1; i < TARGET_STRING_LENGTH; i++) {
+    if (!puzzle_inbounds(puzzle, row - i, column - i)) break;
+    if (puzzle_char_at(puzzle, row - i, column - i) != target_string[i]) break;
+    if (i == TARGET_STRING_LENGTH - 1) count += 1;
+  }
+
+  // up
+  for (int i = 1; i < TARGET_STRING_LENGTH; i++) {
+    if (!puzzle_inbounds(puzzle, row - i, column)) break;
+    if (puzzle_char_at(puzzle, row - i, column) != target_string[i]) break;
+    if (i == TARGET_STRING_LENGTH - 1) count += 1;
+  }
+
+  // up right
+  for (int i = 1; i < TARGET_STRING_LENGTH; i++) {
+    if (!puzzle_inbounds(puzzle, row - i, column + i)) break;
+    if (puzzle_char_at(puzzle, row - i, column + i) != target_string[i]) break;
+    if (i == TARGET_STRING_LENGTH - 1) count += 1;
+  }
+
+  return count;
+}
+
+int main() {
+  char *input = aoc_read_input();
+  int width = strchr(input, '\n') - input + 1;
+  int height = strlen(input) / width;
+
+  Puzzle p;
+  p.text = input;
+  p.width = width;
+  p.height = height;
+
+  int sum = 0;
+
+  for (int i = 0; i < strlen(input); i++) {
+    sum += target_string_count(&p, i);
+  }
+
+  printf("Part 1: %d\n", sum);
+  // printf("Part 2: %d\n", cond_sum);
+
+  aoc_free();
+  return 0;
+}