it is sometimes hard to understand what they ment

day4/second.cpp

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+
+#include <asm-generic/errno.h>
+#include <cstdlib>
+#include <errno.h>
+#include <fstream>
+#include <iostream>
+#include <vector>
+
+#define RANGE 1
+
+int res;
+
+bool AreWeInBounds(int i, int j, std::vector<std::vector<char>> &wordsearch) {
+  if (i < 0 || j < 0) {
+    return false;
+  }
+  if (i >= wordsearch.size() || j >= wordsearch[i].size()) {
+    return false;
+  }
+  return true;
+}
+
+int conditional_operation(int a, int b, char op) {
+  switch (op) {
+  case '+':
+    return a + b;
+  case '-':
+    return a - b;
+  default:
+    return a;
+  }
+}
+
+int Check(std::vector<std::vector<char>> &wordsearch, int i, int j) {
+  int xmases = 0;
+  char op_i;
+  char op_j;
+
+  // array to store the 4 directions
+  /*
+  0 1
+   a
+  2 3
+  */
+  char xarray[4] = {'\0', '\0', '\0', '\0'};
+
+  for (int w = 0; w < 4; w++) {
+    switch (w) {
+    case 0:
+      // search up-left
+      op_i = '-';
+      op_j = '-';
+      if (!AreWeInBounds(i - RANGE, j - RANGE, wordsearch)) {
+        continue;
+      }
+      break;
+    case 1:
+      // search up-right
+      op_i = '-';
+      op_j = '+';
+      if (!AreWeInBounds(i - RANGE, j + RANGE, wordsearch)) {
+        continue;
+      }
+      break;
+    case 2:
+      // search down-left
+      op_i = '+';
+      op_j = '-';
+      if (!AreWeInBounds(i + RANGE, j - RANGE, wordsearch)) {
+        continue;
+      }
+      break;
+    case 3:
+      // search down-right
+      op_i = '+';
+      op_j = '+';
+      if (!AreWeInBounds(i + RANGE, j + RANGE, wordsearch)) {
+        continue;
+      }
+      break;
+    default:
+      std::cerr << "How did we get here?" << std::endl;
+      exit(255);
+      break;
+    }
+    if (wordsearch[i][j] == 'A') {
+      if (wordsearch[conditional_operation(i, 1, op_i)]
+                    [conditional_operation(j, 1, op_j)] == 'M' ||
+
+          wordsearch[conditional_operation(i, 1, op_i)]
+                    [conditional_operation(j, 1, op_j)] == 'S') {
+
+        xarray[w] = wordsearch[conditional_operation(i, 1, op_i)]
+                              [conditional_operation(j, 1, op_j)];
+      }
+    }
+  }
+
+  int ofset = 3;
+  for (int w = 0; w < 2; w++) {
+    if (xarray[w] == 'M' && xarray[w + ofset] == 'S') {
+      xmases++;
+    } else if (xarray[w] == 'S' && xarray[w + ofset] == 'M') {
+      xmases++;
+    }
+    ofset -= 2;
+  }
+  if (xmases == 2) {
+    return 1;
+  } else {
+    return 0;
+  }
+}
+
+int main() {
+  std::ifstream inputfile("input");
+  std::string input;
+
+  res = 0;
+  if (!inputfile.is_open()) {
+    std::cerr << "Could not open the file" << std::endl;
+    return ENOENT;
+  }
+  std::string line;
+  std::vector<std::vector<char>> wordsearch;
+
+  while (std::getline(inputfile, line)) {
+    wordsearch.push_back(std::vector<char>(line.begin(), line.end()));
+  }
+  for (int i = 0; i < wordsearch.size(); i++) {
+    for (int j = 0; j < wordsearch[i].size(); j++) {
+      if (wordsearch[i][j] == 'A') {
+        res += Check(wordsearch, i, j);
+      }
+    }
+  }
+  std::cout << res << std::endl;
+}