diff --git a/day_8/part_1.php b/day_8/part_1.php
new file mode 100644
index 0000000..145d9c9
--- /dev/null
+++ b/day_8/part_1.php
@@ -0,0 +1,15 @@
+<?php
+
+$output = array_map(static function ($line) {
+    return explode('|', $line)[1];
+}, explode("\n", file_get_contents('./input.txt')));
+
+echo array_reduce($output, static function($carry, $item) {
+    $count = 0;
+    $items = explode(' ', $item);
+    foreach ($items as $item) {
+        $count += in_array(strlen($item), [2, 4, 3, 7]) ? 1 : 0;
+    }
+    $carry += $count;
+    return $carry;
+});
\ No newline at end of file
diff --git a/day_8/part_2.php b/day_8/part_2.php
new file mode 100644
index 0000000..ad47021
--- /dev/null
+++ b/day_8/part_2.php
@@ -0,0 +1,99 @@
+<?php
+
+$entries = explode("\n", file_get_contents('./input.txt'));
+
+$outputs = [];
+
+foreach ($entries as $entry) {
+    [$uniques, $output] = explode('|', $entry);
+    $uniques = array_filter(explode(' ', $uniques));
+    $output = array_filter(explode(' ', $output));
+
+    $mapping = [];
+    while (count($mapping) !== 10) {
+        foreach ($uniques as $unique) {
+            $unique = sort_string($unique);
+            if (in_array($unique, $mapping)) {
+                continue;
+            }
+            switch (strlen($unique)) {
+                case 2: $mapping[1] = $unique; break;
+                case 4: $mapping[4] = $unique; break;
+                case 3: $mapping[7] = $unique; break;
+                case 7: $mapping[8] = $unique; break;
+                case 5:
+                    if (array_key_exists(1, $mapping)) {
+                        $segments_1 = str_split($mapping[1]);
+                        if (str_contains($unique, $segments_1[0]) && str_contains($unique, $segments_1[1])) {
+                            $mapping[3] = $unique;
+                            break;
+                        }
+
+                    }
+                    if (array_key_exists(9, $mapping)) {
+                        $segments_9 = str_split($mapping[9]);
+                        $count = 0;
+                        foreach ($segments_9 as $segment_9) {
+                            if (!str_contains($unique, $segment_9)) {
+                                $count++;
+                            }
+                        }
+                        if ($count === 1) {
+                            $mapping[5] = $unique;
+                            break;
+                        } else {
+                            $mapping[2] = $unique;
+                            break;
+                        }
+                    }
+                    break;
+                case 6:
+                    if (array_key_exists(1, $mapping)) {
+                        $segments_1 = str_split($mapping[1]);
+                        if (!str_contains($unique, $segments_1[0]) || !str_contains($unique, $segments_1[1])) {
+                            $mapping[6] = $unique;
+                            break;
+                        }
+                    }
+                    if (array_key_exists(4, $mapping)) {
+                        $segments_4 = str_split($mapping[4]);
+                        if (
+                            str_contains($unique, $segments_4[0]) &&
+                            str_contains($unique, $segments_4[1]) &&
+                            str_contains($unique, $segments_4[2]) &&
+                            str_contains($unique, $segments_4[3])
+                        ) {
+                            $mapping[9] = $unique;
+                            break;
+                        }
+                    }
+                    if (array_key_exists(6, $mapping) && array_key_exists(9, $mapping)) {
+                        $mapping[0] = $unique;
+                        break;
+                    }
+                    break;
+                default:
+                    echo 'unknown length : '.strlen($unique);
+            }
+        }
+    }
+
+    $number = '';
+    foreach ($output as $item) {
+        $item = sort_string($item);
+        $number .= array_search($item, $mapping);
+    }
+
+    echo sprintf('%u%s', $number, "\n");
+    $outputs[] = (int) $number;
+}
+
+echo array_sum($outputs);
+
+function sort_string(string $string)
+{
+    $string = str_split($string);
+    sort($string);
+    return implode($string);
+}
+
diff --git a/day_9/part_1.php b/day_9/part_1.php
new file mode 100644
index 0000000..e4c0f32
--- /dev/null
+++ b/day_9/part_1.php
@@ -0,0 +1,31 @@
+<?php
+
+$grid = array_map(static function ($row) {
+    return str_split($row);
+}, explode("\n", file_get_contents('./input.txt')));
+
+$low_points = [];
+
+foreach ($grid as $i => $row) {
+    foreach ($row as $j => $cell) {
+        $count = 0;
+        if (!array_key_exists($i - 1, $grid) || $grid[$i - 1][$j] > $cell) {
+            $count++;
+        }
+        if (!array_key_exists($i + 1, $grid) || $grid[$i + 1][$j] > $cell) {
+            $count++;
+        }
+        if (!array_key_exists($j - 1, $row) ||$row[$j - 1] > $cell) {
+            $count++;
+        }
+        if (!array_key_exists($j + 1, $row) || $row[$j + 1] > $cell) {
+            $count++;
+        }
+
+        if ($count === 4) {
+            $low_points[] = (int) $cell;
+        }
+    }
+}
+
+echo array_sum($low_points) + count($low_points);
\ No newline at end of file