添加0112.路径总和.mdJava解法

problems/0112.路径总和.md

@@ -411,6 +411,31 @@ class solution {
 }
 ```
 
+```java
+// 解法2
+class Solution {
+    List<List<Integer>> result;
+    LinkedList<Integer> path;
+    public List<List<Integer>> pathSum (TreeNode root,int targetSum) {
+        result = new LinkedList<>();
+        path = new LinkedList<>();
+        travesal(root, targetSum);
+        return result;
+    }
+    private void travesal(TreeNode root,  int count) {
+        if (root == null) return;
+        path.offer(root.val);
+        count -= root.val;
+        if (root.left == null && root.right == null && count == 0) {
+            result.add(new LinkedList<>(path));
+        }
+        travesal(root.left, count);
+        travesal(root.right, count);
+        path.removeLast(); // 回溯
+    }
+}
+```
+
 ## python
 
 0112.路径总和