Heap bonus!

src/heap.rs

@@ -0,0 +1,25 @@
+#[derive(Debug)]
+pub struct Heap {
+    pub heaps: Vec<Vec<i32>>
+}
+
+impl Heap {
+    pub fn new() -> Heap {
+        Heap {
+            heaps: Vec::new()
+        }
+    }
+
+    pub fn len(&self) -> usize {
+        self.heaps.len()
+    }
+
+    pub fn get(&mut self, i: usize) -> &mut Vec<i32> {
+        &mut self.heaps[i]
+    }
+
+    pub fn alloc(&mut self, size: usize) -> usize {
+        self.heaps.push(vec![0; size]);
+        self.len() - 1
+    }
+}