feat: day02 (#4)

* feat: rust

* feat: c and c++

.github/workflows/test.yaml

@@ -69,8 +69,10 @@ jobs:
         uses: actions/checkout@v3
 
       - name: Build
-        run: g++ ./cpp/*.cc
-
+        run: |
+          for file in cpp/*.cc; do
+              g++ "$file" -o "${file%.cc}"
+          done
   cpp-clang-build:
     name: Build C++ with clang
     runs-on: ubuntu-latest
@@ -80,7 +82,10 @@ jobs:
         uses: actions/checkout@v3
 
       - name: Build
-        run: clang++ ./cpp/*.cc
+        run: |
+          for file in cpp/*.cc; do
+              clang++ "$file" -o "${file%.cc}"
+          done
 
   gcc-build:
     name: Build C with gcc
@@ -91,7 +96,10 @@ jobs:
         uses: actions/checkout@v3
 
       - name: Build
-        run: gcc ./c/*.c
+        run: |
+          for file in c/*.c; do
+              gcc "$file" -o "${file%.c}"
+          done
 
   clang-build:
     name: Build C with clang
@@ -102,4 +110,7 @@ jobs:
         uses: actions/checkout@v3
 
       - name: Build
-        run: clang ./c/*.c
+        run: |
+          for file in c/*.c; do
+              clang "$file" -o "${file%.c}"
+          done

Cargo.toml

@@ -1,6 +1,6 @@
 [workspace]
 resolver = "2"
-members = ["crates/day01"]
+members = ["crates/day01", "crates/day02"]
 
 [profile.release]
 opt-level = 'z'

README.md

@@ -4,9 +4,12 @@ This is my advent of code 2024 adventure!
 
 My goal this year is (I hope so) to resolve everyday challenges using rust. If I have time, I create a solution for C/C++.
 
+Ideally, the solution does not use external crates/dependencies.
+
 ## Solutions
 
 |  Day  |  Rust  |        |  C++   |        |   C    |        |
 | :---: | :----: | :----: | :----: | :----: | :----: | :----: |
 |       | Part 1 | Part 2 | Part 1 | Part 2 | Part 1 | Part 2 |
-|   1   |   ✅    |   ✅    |   ✅    |   ✅    |   ✅    | ✅      |
+|   1   |   ✅    |   ✅    |   ✅    |   ✅    |   ✅    |   ✅    |
+|   2   |   ✅    |   ✅    |   ✅    |   ✅    |   ✅    |   ✅    |

c/day02.c

@@ -0,0 +1,115 @@
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#define MAX_LINE_LENGTH 256
+#define MAX_VALUES 100
+
+bool has_small_difference(int *vec, size_t size) {
+  for (size_t i = 0; i < size - 1; ++i) {
+    int diff = abs(vec[i + 1] - vec[i]);
+    if (diff < 1 || diff > 3) {
+      return false;
+    }
+  }
+  return true;
+}
+
+bool is_safe(int *e, size_t size) {
+  bool non_increasing = true;
+  bool non_decreasing = true;
+
+  for (size_t i = 0; i < size - 1; ++i) {
+    if (e[i] < e[i + 1]) {
+      non_increasing = false;
+    }
+    if (e[i] > e[i + 1]) {
+      non_decreasing = false;
+    }
+  }
+
+  return (non_increasing || non_decreasing) && has_small_difference(e, size);
+}
+
+int **read_file(const char *input, size_t *row_count) {
+  FILE *file = fopen(input, "r");
+  if (!file) {
+    perror("Failed to open file");
+    return NULL;
+  }
+
+  int **report = malloc(MAX_VALUES * sizeof(int *));
+  *row_count = 0;
+
+  char line[MAX_LINE_LENGTH];
+  while (fgets(line, sizeof(line), file) && *row_count < MAX_VALUES) {
+    int *row = malloc(MAX_VALUES * sizeof(int));
+    char *token = strtok(line, " ");
+    size_t col_count = 0;
+
+    while (token != NULL) {
+      row[col_count++] = atoi(token);
+      token = strtok(NULL, " ");
+    }
+    report[*row_count] = realloc(row, col_count * sizeof(int));
+    (*row_count)++;
+  }
+
+  fclose(file);
+  return report;
+}
+
+int main() {
+  size_t row_count;
+  int **report = read_file("crates/day02/input.txt", &row_count);
+  if (!report) {
+    return EXIT_FAILURE;
+  }
+
+  // --- Part One ---
+  unsigned int safe_count = 0;
+  for (size_t i = 0; i < row_count; ++i) {
+    if (is_safe(report[i], MAX_VALUES)) {
+      safe_count++;
+    }
+  }
+  printf("Part One solution: sum is %u\n", safe_count);
+
+  // --- Part Two ---
+  safe_count = 0;
+  for (size_t i = 0; i < row_count; ++i) {
+    if (is_safe(report[i], MAX_VALUES)) {
+      safe_count++;
+    } else {
+      for (size_t pos = 0; pos < MAX_VALUES; ++pos) {
+        if (report[i][pos] == 0)
+          continue;
+        int *new = malloc((MAX_VALUES - 1) * sizeof(int));
+        size_t new_count = 0;
+
+        for (size_t j = 0; j < MAX_VALUES; ++j) {
+          if (j != pos) {
+            new[new_count++] = report[i][j];
+          }
+        }
+
+        if (is_safe(new, new_count)) {
+          safe_count++;
+          free(new);
+          break;
+        }
+
+        free(new);
+      }
+    }
+  }
+  printf("Part Two solution: sum is %u\n", safe_count);
+
+  for (size_t i = 0; i < row_count; ++i) {
+    free(report[i]);
+  }
+  free(report);
+
+  return 0;
+}

cpp/day02.cc

@@ -0,0 +1,76 @@
+#include <algorithm>
+#include <cmath>
+#include <fstream>
+#include <iostream>
+#include <sstream>
+#include <vector>
+
+bool has_small_difference(const std::vector<int> &vec) {
+  for (size_t i = 0; i < vec.size() - 1; ++i) {
+    int diff = std::abs(vec[i + 1] - vec[i]);
+    if (diff < 1 || diff > 3) {
+      return false;
+    }
+  }
+  return true;
+}
+
+bool is_safe(const std::vector<int> &e) {
+  bool test = has_small_difference(e);
+  bool all_non_increasing =
+      std::is_sorted(e.begin(), e.end(), std::greater<int>());
+  bool all_non_decreasing = std::is_sorted(e.begin(), e.end());
+  return (all_non_increasing || all_non_decreasing) && test;
+}
+
+std::vector<std::vector<int>> read_file(const std::string &input) {
+  std::vector<std::vector<int>> report;
+  std::ifstream file(input);
+  std::string line;
+
+  while (std::getline(file, line)) {
+    std::istringstream iss(line);
+    std::vector<int> row;
+    int num;
+    while (iss >> num) {
+      row.push_back(num);
+    }
+    report.push_back(row);
+  }
+
+  return report;
+}
+
+int main() {
+  // --- Part One ---
+  auto report = read_file("crates/day02/input.txt");
+  unsigned int safe = 0;
+
+  for (const auto &e : report) {
+    if (is_safe(e)) {
+      safe++;
+    }
+  }
+  std::cout << "Part One solution: sum is " << safe << std::endl;
+
+  // --- Part Two ---
+  safe = 0;
+  for (const auto &e : report) {
+    if (is_safe(e)) {
+      safe++;
+    } else {
+      for (size_t pos = 0; pos < e.size(); ++pos) {
+        std::vector<int> new_e = e;
+        new_e.erase(new_e.begin() + pos);
+
+        if (is_safe(new_e)) {
+          safe++;
+          break;
+        }
+      }
+    }
+  }
+  std::cout << "Part Two solution: sum is " << safe << std::endl;
+
+  return 0;
+}

crates/day01/Cargo.toml

@@ -7,4 +7,5 @@ edition = "2021"
 workspace = true
 
 [features]
+default = ["unstable"]
 unstable = []

crates/day02/Cargo.toml

@@ -0,0 +1,7 @@
+[package]
+name = "day02"
+version = "0.1.0"
+edition = "2021"
+
+[lints]
+workspace = true