1 files changed, 27 insertions, 0 deletions
diff --git a/src/row.rs b/src/row.rs
new file mode 100644
index 0000000..fc0633b
--- /dev/null
+++ b/src/row.rs
@@ -0,0 +1,27 @@
+pub fn encode_row(n: u32, mut x: u64) -> Vec<u32> {
+    let mut row = Vec::with_capacity(n as usize);
+    let mut pieces: Vec<u32> = (0..n).collect();
+    for i in (1..=n.into()).rev() {
+        let p = (x % i) as u32;
+        let piece = pieces[p as usize];
+        row.push(piece + 1);
+        pieces.swap_remove(p as usize);
+        x /= i;
+    }
+    row
+}
+
+pub fn colliding(w1: &[u32], w2: &[u32]) -> bool {
+    let n = w1.len() - 1;
+    let (mut v1, mut v2) = (w1.iter().take(n), w2.iter().take(n));
+    let (mut i, mut j) = (*v1.next().unwrap(), *v2.next().unwrap());
+    loop {
+        if i < j {
+            i += if let Some(&k) = v1.next() { k } else { return false; };
+        } else if i > j {
+            j += if let Some(&k) = v2.next() { k } else { return false; };
+        } else {
+            return true;
+        }
+    }
+}