diff --git a/input/10-0a.in b/input/10-0a.in
new file mode 100644
index 0000000..a305b9d
--- /dev/null
+++ b/input/10-0a.in
@@ -0,0 +1,4 @@
+0123
+1234
+8765
+9876
diff --git a/input/10-0b.in b/input/10-0b.in
new file mode 100644
index 0000000..cada9b3
--- /dev/null
+++ b/input/10-0b.in
@@ -0,0 +1,8 @@
+89010123
+78121874
+87430965
+96549874
+45678903
+32019012
+01329801
+10456732
diff --git a/input/10-0c.in b/input/10-0c.in
new file mode 100644
index 0000000..cada9b3
--- /dev/null
+++ b/input/10-0c.in
@@ -0,0 +1,8 @@
+89010123
+78121874
+87430965
+96549874
+45678903
+32019012
+01329801
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diff --git a/input/10-1.in b/input/10-1.in
new file mode 100644
index 0000000..d18cbd9
--- /dev/null
+++ b/input/10-1.in
@@ -0,0 +1,45 @@
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diff --git a/src/bin/10.rs b/src/bin/10.rs
new file mode 100644
index 0000000..29ffdaa
--- /dev/null
+++ b/src/bin/10.rs
@@ -0,0 +1,58 @@
+use std::collections::HashSet;
+
+fn count_paths<C>(map: &[Vec<u8>], x: usize, y: usize) -> C
+where
+    C: Extend<(usize, usize)>
+        + From<[(usize, usize); 1]>
+        + Default
+        + IntoIterator<Item = (usize, usize)>,
+{
+    [(1, 0), (0, 1), (-1, 0), (0, -1)]
+        .into_iter()
+        .filter_map(|(dx, dy)| {
+            Option::zip(
+                x.checked_add_signed(dx).filter(|nx| *nx < map[0].len()),
+                y.checked_add_signed(dy).filter(|&ny| ny < map.len()),
+            )
+        })
+        .filter(|&(nx, ny)| map[y][x] + 1 == map[ny][nx])
+        .map(|(nx, ny)| {
+            if map[ny][nx] == 9 {
+                C::from([(nx, ny)])
+            } else {
+                count_paths::<C>(map, nx, ny)
+            }
+        })
+        .reduce(|mut a, b| {
+            a.extend(b);
+            a
+        })
+        .unwrap_or(C::default())
+}
+
+fn main() {
+    let text = std::fs::read_to_string("input/10-1.in").unwrap();
+
+    let map = text
+        .lines()
+        .map(|l| {
+            l.chars()
+                .map(|c| c.to_digit(10).unwrap() as u8)
+                .collect::<Vec<_>>()
+        })
+        .collect::<Vec<_>>();
+
+    let mut sum1 = 0;
+    let mut sum2 = 0;
+    for (x, y, _) in map
+        .iter()
+        .enumerate()
+        .flat_map(|(y, l)| l.iter().enumerate().map(move |(x, c)| (x, y, c)))
+        .filter(|(_, _, c)| **c == 0)
+    {
+        sum1 += count_paths::<HashSet<_>>(&map, x, y).len();
+        sum2 += count_paths::<Vec<_>>(&map, x, y).len();
+    }
+
+    println!("{sum1}\n{sum2}")
+}