Solve leetcode 572

src/lc572.rs

@@ -0,0 +1,55 @@
+use std::rc::Rc;
+use std::cell::RefCell;
+use std::path::Iter;
+
+type Tree = Option<Rc<RefCell<TreeNode>>>;
+
+#[derive(Debug, PartialEq, Eq)]
+pub struct TreeNode {
+    pub val: i32,
+    pub left: Tree,
+    pub right: Tree,
+}
+
+impl TreeNode {
+    #[inline]
+    pub fn new(val: i32) -> Self {
+        TreeNode {
+            val,
+            left: None,
+            right: None,
+        }
+    }
+}
+
+struct Solution {}
+
+impl Solution {
+    pub fn is_subtree(root: Tree, sub_root: Tree) -> bool {
+        dfs_fits(&root, &sub_root)
+    }
+}
+
+fn same(t1: &Tree, t2: &Tree) -> bool {
+    if t2.is_none() || t1.is_none() {
+        return t1 == t2;
+    }
+    let t1 = t1.as_ref().unwrap().borrow();
+    let t2 = t2.as_ref().unwrap().borrow();
+    return t1.val == t2.val &&
+        same(&t1.left, &t2.left) &&
+        same(&t1.right, &t2.right);
+}
+
+fn dfs_fits(tree: &Tree, shape: &Tree) -> bool {
+    match &tree {
+        None => shape.is_none(),
+        Some(t) => {
+            if same(&tree, &shape) {
+                return true;
+            }
+            dfs_fits(&t.borrow().left, &shape) ||
+                dfs_fits(&t.borrow().right, &shape)
+        }
+    }
+}

src/lib.rs

@@ -6,3 +6,5 @@ pub mod lc143;
 pub mod lc206;
 pub mod lc22;
 pub mod lc739;
+
+pub mod lc572;