feat: add rust solution to lcof problem: No.34

面试题34. 二叉树中和为某一值的路径

Author: YangFong

Diff for: lcof/面试题34. 二叉树中和为某一值的路径/README.md

@@ -280,6 +280,55 @@ function pathSum(root: TreeNode | null, target: number): number[][] {
 use std::cell::RefCell;
 use std::rc::Rc;
 
+impl Solution {
+    fn dfs(
+        root: &Option<Rc<RefCell<TreeNode>>>,
+        mut target: i32,
+        paths: &mut Vec<i32>,
+        res: &mut Vec<Vec<i32>>,
+    ) {
+        if let Some(node) = root.as_ref() {
+            let node = node.borrow();
+            paths.push(node.val);
+            target -= node.val;
+            if node.left.is_none() && node.right.is_none() && target == 0 {
+                res.push(paths.clone());
+            }
+            Solution::dfs(&node.left, target, paths, res);
+            Solution::dfs(&node.right, target, paths, res);
+            paths.pop();
+        }
+    }
+    pub fn path_sum(root: Option<Rc<RefCell<TreeNode>>>, target: i32) -> Vec<Vec<i32>> {
+        let mut res = vec![];
+        Solution::dfs(&root, target, &mut vec![], &mut res);
+        res
+    }
+}
+```
+
+```rust
+// 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::cell::RefCell;
+use std::rc::Rc;
+
 impl Solution {
     fn dfs(
         root: &Option<Rc<RefCell<TreeNode>>>,

Diff for: lcof/面试题34. 二叉树中和为某一值的路径/Solution.rs

@@ -24,38 +24,23 @@ impl Solution {
         root: &Option<Rc<RefCell<TreeNode>>>,
         mut target: i32,
         paths: &mut Vec<i32>,
-    ) -> Vec<Vec<i32>> {
-        let node = root.as_ref().unwrap().borrow();
-        paths.push(node.val);
-        target -= node.val;
-        let mut res = vec![];
-        // 确定叶结点身份
-        if node.left.is_none() && node.right.is_none() {
-            if target == 0 {
+        res: &mut Vec<Vec<i32>>,
+    ) {
+        if let Some(node) = root.as_ref() {
+            let node = node.borrow();
+            paths.push(node.val);
+            target -= node.val;
+            if node.left.is_none() && node.right.is_none() && target == 0 {
                 res.push(paths.clone());
             }
+            Solution::dfs(&node.left, target, paths, res);
+            Solution::dfs(&node.right, target, paths, res);
             paths.pop();
-            return res;
-        }
-        if node.left.is_some() {
-            let res_l = Solution::dfs(&node.left, target, paths);
-            if !res_l.is_empty() {
-                res = [res, res_l].concat();
-            }
-        }
-        if node.right.is_some() {
-            let res_r = Solution::dfs(&node.right, target, paths);
-            if !res_r.is_empty() {
-                res = [res, res_r].concat();
-            }
         }
-        paths.pop();
-        res
     }
     pub fn path_sum(root: Option<Rc<RefCell<TreeNode>>>, target: i32) -> Vec<Vec<i32>> {
-        if root.is_none() {
-            return vec![];
-        }
-        Solution::dfs(&root, target, &mut vec![])
+        let mut res = vec![];
+        Solution::dfs(&root, target, &mut vec![], &mut res);
+        res
     }
 }