✨ Commence le jour 8

day_8/part_1.php

@@ -0,0 +1,43 @@
+<?php
+
+$map = array_map('str_split', explode("\n", file_get_contents('./input.txt')));
+
+$numRows = count($map);
+$numCols = count($map[0]);
+$visibles = ($numRows - 2) * 2 + ($numCols * 2); // edges
+
+for ($i = 1; $i <= $numRows - 2; $i++) {
+    for ($j = 1; $j <= $numCols - 2; $j++) {
+        if (isVisible($i, $j, $map)) {
+            $visibles++;
+            echo sprintf('{%u, %u} {%u} is visible %s', $i, $j, $map[$i][$j], "\n");
+        } else {
+            echo sprintf('{%u, %u} {%u} is NOT visible %s', $i, $j, $map[$i][$j], "\n");
+        }
+    }
+}
+
+echo $visibles;
+
+/**
+ * @param int   $x
+ * @param int   $y
+ * @param array $map
+ *
+ * @return bool
+ */
+function isVisible(int $x, int $y, array $map): bool
+{
+    $currentNumber = (int)$map[$x][$y];
+    $row = $map[$x];
+    if (max(array_slice($row, 0, $y)) < $currentNumber || max(array_slice($row, $y + 1)) < $currentNumber) {
+        return true;
+    }
+
+    array_unshift($map, null);
+    $map = array_map(...$map);
+
+    $col = $map[$y];
+
+    return max(array_slice($col, 0, $x)) < $currentNumber || max(array_slice($col, $x + 1)) < $currentNumber;
+}