Update 二叉树相关.md

blogs/Algorithm/剑指 Offer/二叉树相关.md

@@ -165,3 +165,32 @@ class Solution {
 }
 ```
 
+#### [ Offer 34. 二叉树中和为某一值的路径](https://leetcode-cn.com/problems/er-cha-shu-zhong-he-wei-mou-yi-zhi-de-lu-jing-lcof/)
+
+```java
+class Solution {
+
+    List<List<Integer>> result = new ArrayList<>();
+    List<Integer> path = new ArrayList<>();
+
+    public List<List<Integer>> pathSum(TreeNode root, int sum) {
+        path(root, sum);
+        return result;
+    }
+
+    private void path(TreeNode root, int sum) {
+        if (root == null) {
+            return;
+        }
+        path.add(root.val);
+        int target = sum - root.val;
+        if (target == 0 && root.left == null && root.right == null) {
+            result.add(new ArrayList(path));
+        }
+        path(root.left, target);
+        path(root.right, target);
+        path.remove(path.size() - 1);
+    }
+}
+```
+