day 4 done. oat beat me

src/day-4-solution.cpp

@@ -0,0 +1,126 @@
+#include "spdlog/spdlog.h"
+#include <cstdint>
+#include <fstream>
+#include <string>
+#include <sys/types.h>
+#include <utility>
+#include <vector>
+
+std::vector<std::vector<uint8_t>> parse_matrix(const std::vector<std::string>& matrix_lines){
+  std::vector<std::vector<uint8_t>> returnable = std::vector<std::vector<uint8_t>> {};
+
+  for (std::string line  : matrix_lines) {
+    std::vector<uint8_t> temp_vector = std::vector<uint8_t>{};
+
+    for (std::string::const_iterator i = line.begin(); i<line.end(); i++) {
+      if(*i=='@')temp_vector.push_back(uint8_t {1});
+      else temp_vector.push_back(uint8_t {0});
+    }
+    returnable.push_back(temp_vector);
+  }
+  return returnable;
+} 
+
+std::vector<std::vector<uint8_t>> construct_kernel(uint8_t r){
+  std::vector<std::vector<uint8_t>> kernel = std::vector<std::vector<uint8_t>> {};
+  
+  for (int r_1 = int {-1 * r}; r_1<=r; r_1++) {
+    std::vector<uint8_t> row = std::vector<uint8_t> {};
+    for (int r_2 = int {-1*r}; r_2<=r; r_2++) {
+
+      if(r_1 != 0 || r_2!=0) row.push_back(uint8_t {1});
+      else row.push_back(uint8_t {0});
+    }
+    kernel.push_back(row);
+  }
+  return kernel;
+}
+
+int convolve(
+    const std::vector<std::vector<uint8_t>>& matrix,
+    int r,                          // radius of the kernel
+    int i,                          // row index of the target cell
+    int j,                          // column index of the target cell
+    const std::vector<std::vector<uint8_t>>& kernel
+) {
+    int sum = 0;
+
+    int rows = matrix.size();
+    int cols = matrix[i].size();
+
+    for (int dr = -r; dr <= r; dr++) {
+        for (int dc = -r; dc <= r; dc++) {
+            int ni = i + dr; 
+            int nj = j + dc; 
+
+
+            if (ni < 0 || ni >= rows || nj < 0 || nj >= cols) continue;
+
+
+            int kr = dr + r;
+            int kc = dc + r;
+
+            sum += matrix[ni][nj] * kernel[kr][kc];
+        }
+    }
+
+    return sum;
+}
+
+int solve_part_one( const std::vector<std::vector<uint8_t>>& matrix){
+  const std::vector<std::vector<uint8_t>> kernel = construct_kernel(1);
+  int returnable = int {0};
+  for (int i = {0}; i<matrix.size(); i++) {
+    for (int j = {0}; j<matrix[i].size();j++) {
+      if(matrix[i][j]==1){
+        returnable += convolve(matrix, 1, i, j, kernel)<4 ? 1 : 0;
+      }
+    }
+  }
+  return returnable;
+}
+
+int solve_part_two( std::vector<std::vector<uint8_t>>& matrix){
+  static const std::vector<std::vector<uint8_t>> kernel = construct_kernel(1);
+  int returnable = int {0};
+  std::vector<std::pair<int,int>> indicies = std::vector<std::pair<int,int>> {};
+  for (int i = {0}; i<matrix.size(); i++) {
+    for (int j = {0}; j<matrix[i].size();j++) {
+      if(matrix[i][j]==1){
+        int convolution = convolve(matrix, 1, i, j, kernel);
+        if(convolution <4){
+          indicies.push_back(std::pair<int, int>{i,j});
+          returnable+=1;
+        }
+      }
+    }
+
+
+  }
+  if(indicies.size()==0)return returnable;
+  for (std::pair<int,int> pair: indicies) {
+      matrix[pair.first][pair.second] = 0;
+  }
+  returnable+=solve_part_two(matrix);
+  return returnable;
+}
+
+int main () {
+  std::ifstream input = std::ifstream{"testcases/day-4.in", std::ios_base::binary};
+  std::vector<std::string> lines = std::vector<std::string> {};
+  std::string current_line = std::string{};
+
+  while (std::getline(input, current_line)) {
+    lines.push_back(current_line);
+  }
+  std::vector<std::vector<uint8_t>> testcase = parse_matrix(lines);
+
+  int part_one_solution = solve_part_one(testcase);
+  spdlog::info("Part one solution: {}", part_one_solution);
+
+  int part_two_solution = solve_part_two(testcase);
+  spdlog::info("Part two solution: {}", part_two_solution);
+
+
+  return 0;
+}