[rust] Pascal's Triangle

1 files changed, 34 insertions, 0 deletions

diff --git a/pascals-triangle/src/lib.rs b/pascals-triangle/src/lib.rs
new file mode 100644
index 0000000..7b2145b
--- /dev/null
+++ b/pascals-triangle/src/lib.rs
@@ -0,0 +1,34 @@
+#[derive(Debug)]
+pub struct PascalsTriangle {
+    rows: Vec<Vec<u32>>,
+}
+
+impl PascalsTriangle {
+    fn next_row(row: &[u32]) -> Vec<u32> {
+        let mut next = Vec::new();
+        let last = row.iter().fold(0, |p, n| {
+            next.push(p + n);
+            *n
+        });
+        next.push(last);
+        next
+    }
+}
+
+impl PascalsTriangle {
+    pub fn new(row_count: u32) -> Self {
+        let mut rows = Vec::new();
+        if row_count > 0 {
+            rows.push(vec![1]);
+            (1..row_count).for_each(|i| {
+                let irow = Self::next_row(&rows[(i as usize) - 1]);
+                rows.push(irow);
+            })
+        }
+        PascalsTriangle { rows }
+    }
+
+    pub fn rows(&self) -> Vec<Vec<u32>> {
+        self.rows.clone()
+    }
+}