feat: day 03 c and c++ (#5)

* feat: day 03 c and c++

* fix: simplify c

.github/workflows/test.yaml

@@ -73,19 +73,6 @@ jobs:
           for file in cpp/*.cc; do
               g++ "$file" -o "${file%.cc}"
           done
-  cpp-clang-build:
-    name: Build C++ with clang
-    runs-on: ubuntu-latest
-
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v3
-
-      - name: Build
-        run: |
-          for file in cpp/*.cc; do
-              clang++ "$file" -o "${file%.cc}"
-          done
 
   gcc-build:
     name: Build C with gcc
@@ -100,17 +87,3 @@ jobs:
           for file in c/*.c; do
               gcc "$file" -o "${file%.c}"
           done
-
-  clang-build:
-    name: Build C with clang
-    runs-on: ubuntu-latest
-
-    steps:
-      - name: Checkout code
-        uses: actions/checkout@v3
-
-      - name: Build
-        run: |
-          for file in c/*.c; do
-              clang "$file" -o "${file%.c}"
-          done

Cargo.toml

@@ -6,7 +6,7 @@ members = ["crates/day01", "crates/day02", "crates/day03"]
 regex = "1.11.1"
 
 [profile.release]
-opt-level = 'z'
+opt-level = 3
 lto = true
 codegen-units = 1
 panic = 'abort'

README.md

@@ -13,4 +13,4 @@ Ideally, the solution does not use external crates/dependencies.
 |       | Part 1 | Part 2 | Part 1 | Part 2 | Part 1 | Part 2 |
 |   1   |   ✅    |   ✅    |   ✅    |   ✅    |   ✅    |   ✅    |
 |   2   |   ✅    |   ✅    |   ✅    |   ✅    |   ✅    |   ✅    |
-|   3   |   ✅    |   ✅    |   ❌    |   ❌    |   ❌    |   ❌    |
+|   3   |   ✅    |   ✅    |   ✅    |   ✅    |   ✅    |   ✅    |

c/day03.c

@@ -0,0 +1,188 @@
+#include <ctype.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+typedef struct {
+  const char *iterator;
+  const char *end;
+} ProgramParser;
+
+static inline char peek(const ProgramParser *parser) {
+  return (parser->iterator < parser->end) ? *parser->iterator : '\0';
+}
+
+static inline void next(ProgramParser *parser) {
+  if (parser->iterator < parser->end)
+    parser->iterator++;
+}
+
+static bool parse_mul(ProgramParser *parser) {
+  if (parser->end - parser->iterator < 3)
+    return false;
+  if (strncmp(parser->iterator, "mul", 3) == 0) {
+    parser->iterator += 3;
+    return true;
+  }
+  return false;
+}
+
+static int parse_number(ProgramParser *parser) {
+  int value = 0, count = 0;
+
+  while (isdigit(peek(parser)) && count < 3) {
+    value = value * 10 + (peek(parser) - '0');
+    next(parser);
+    count++;
+  }
+
+  return count > 0 ? value : -1;
+}
+
+static int parse(ProgramParser *parser) {
+  int result = 0;
+
+  while (parser->iterator < parser->end) {
+    if (parse_mul(parser) && peek(parser) == '(') {
+      next(parser);
+      int a = parse_number(parser);
+
+      if (a != -1 && peek(parser) == ',') {
+        next(parser);
+        int b = parse_number(parser);
+
+        if (b != -1 && peek(parser) == ')') {
+          next(parser);
+          result += a * b;
+        }
+      }
+    } else {
+      next(parser);
+    }
+  }
+
+  return result;
+}
+
+typedef struct {
+  size_t *data;
+  size_t size;
+  size_t capacity;
+} SizeVector;
+
+static SizeVector create_size_vector(size_t initial_capacity) {
+  SizeVector vec = {.data = malloc(initial_capacity * sizeof(size_t)),
+                    .size = 0,
+                    .capacity = initial_capacity};
+  return vec;
+}
+
+static void free_size_vector(SizeVector *vec) { free(vec->data); }
+
+static void push_back(SizeVector *vec, size_t value) {
+  if (vec->size == vec->capacity) {
+    vec->capacity = (vec->capacity * 3) / 2; // 1.5x growth
+    vec->data = realloc(vec->data, vec->capacity * sizeof(size_t));
+  }
+  vec->data[vec->size++] = value;
+}
+
+static SizeVector find_all_indexes(const char *haystack, const char *needle) {
+  SizeVector indexes = create_size_vector(16);
+  const size_t needle_len = strlen(needle);
+  const char *pos = haystack;
+
+  while ((pos = strstr(pos, needle)) != NULL) {
+    push_back(&indexes, pos - haystack);
+    pos += needle_len;
+  }
+
+  return indexes;
+}
+
+int closest_greater_than(size_t x, const SizeVector *values) {
+  int closest = -1;
+  for (size_t i = 0; i < values->size; i++) {
+    if (values->data[i] > x && (closest == -1 || values->data[i] < closest)) {
+
+      closest = values->data[i];
+    }
+  }
+  return closest;
+}
+
+static int count_mul(const char *message) {
+  ProgramParser parser = {.iterator = message,
+                          .end = message + strlen(message)};
+  return parse(&parser);
+}
+
+static int parse_with_rules(const char *message) {
+  const char *do_substring = "do()";
+  const char *dont_substring = "don't()";
+
+  SizeVector do_positions = find_all_indexes(message, do_substring);
+  SizeVector dont_positions = find_all_indexes(message, dont_substring);
+
+  if (do_positions.size == 0 && dont_positions.size == 0) {
+    int result = count_mul(message);
+    free_size_vector(&do_positions);
+    free_size_vector(&dont_positions);
+    return result;
+  }
+
+  size_t len = do_positions.data[0] + strlen(do_substring);
+  char *first_substring = strndup(message, len);
+  int count = count_mul(first_substring);
+  free(first_substring);
+
+  int next_dont = -1;
+
+  for (size_t i = 0; i < do_positions.size; i++) {
+    size_t pos = do_positions.data[i];
+    if (next_dont == -1 || pos > next_dont) {
+      int next_dont_opt = closest_greater_than(pos, &dont_positions);
+      if (next_dont_opt != -1) {
+        size_t substring_len = next_dont_opt - pos;
+        char *substring = strndup(message + pos, substring_len);
+        count += count_mul(substring);
+        free(substring);
+        next_dont = next_dont_opt;
+      }
+    }
+  }
+
+  free_size_vector(&do_positions);
+  free_size_vector(&dont_positions);
+
+  return count;
+}
+
+static char *read_file(const char *file_path) {
+  FILE *file = fopen(file_path, "r");
+  if (!file) {
+    perror("Unable to open file");
+    exit(EXIT_FAILURE);
+  }
+
+  fseek(file, 0, SEEK_END);
+  long file_size = ftell(file);
+  rewind(file);
+
+  char *content = malloc(file_size + 1);
+  fread(content, 1, file_size, file);
+  content[file_size] = '\0';
+  fclose(file);
+  return content;
+}
+
+int main() {
+  char *message = read_file("crates/day03/input.txt");
+
+  printf("Part One solution: sum is %d\n", count_mul(message));
+  printf("Part Two solution: sum is %d\n", parse_with_rules(message));
+
+  free(message);
+  return 0;
+}