src/bin/binary-tree-paths.rs

Author: bestgopher

src/bin/binary-tree-paths.rs

@@ -0,0 +1,67 @@
+fn main() {}
+
+struct Solution;
+
+// Definition for a binary tree node.
+#[derive(Debug, PartialEq, Eq)]
+pub struct TreeNode {
+    pub val: i32,
+    pub left: Option<Rc<RefCell<TreeNode>>>,
+    pub right: Option<Rc<RefCell<TreeNode>>>,
+}
+
+impl TreeNode {
+    #[inline]
+    pub fn new(val: i32) -> Self {
+        TreeNode {
+            val,
+            left: None,
+            right: None,
+        }
+    }
+}
+
+use std::rc::Rc;
+use std::cell::RefCell;
+
+impl Solution {
+    pub fn binary_tree_paths(root: Option<Rc<RefCell<TreeNode>>>) -> Vec<String> {
+        let s = Self::f(root);
+        s.into_iter().map(|x| x.into_iter().map(|y| y.to_string()).collect::<Vec<String>>().join("->")).collect()
+    }
+
+    fn f(root: Option<Rc<RefCell<TreeNode>>>) -> Vec<Vec<i32>> {
+        if root.is_none() {
+            return vec![];
+        }
+
+        let left = root.as_ref().unwrap().borrow_mut().left.take();
+        let right = root.as_ref().unwrap().borrow_mut().right.take();
+        let v = root.as_ref().unwrap().borrow().val;
+        match (left, right) {
+            (Some(x), Some(y)) => {
+                let f = Self::f(Some(x));
+                let r = Self::f(Some(y));
+                f.into_iter().chain(r.into_iter()).map(|mut x| {
+                    x.insert(0, v);
+                    x
+                }).collect::<Vec<Vec<i32>>>()
+            }
+            (Some(x), None) => {
+                let f = Self::f(Some(x));
+                f.into_iter().map(|mut x| {
+                    x.insert(0, v);
+                    x
+                }).collect::<Vec<Vec<i32>>>()
+            }
+            (None, Some(y)) => {
+                let f = Self::f(Some(y));
+                f.into_iter().map(|mut x| {
+                    x.insert(0, v);
+                    x
+                }).collect::<Vec<Vec<i32>>>()
+            }
+            (None, None) => vec![vec![v]]
+        }
+    }
+}