[isSymmetric && pathSum ii]

Sample.java

@@ -4,4 +4,33 @@
 // Any problem you faced while coding this :
 
 
-// Your code here along with comments explaining your approach
+// Your code here along with comments explaining your approach
+
+public class Sample {
+    // Time Complexity : O(n)
+    // Space Complexity : O(h)
+    // Did this code successfully run on Leetcode : yes
+    List<List<Integer>> ans = new ArrayList<>();
+    public List<List<Integer>> pathSum(TreeNode root, int targetSum) {
+        int currSum = 0;
+
+        helper(root, currSum, new ArrayList<>(), targetSum);
+        return ans;
+    }
+
+    public void helper(TreeNode root, int currSum, List<Integer> list, int tar) {
+        if (root == null) return;
+        currSum = currSum + root.val;
+        System.out.println(root.val + " " + currSum + " " + tar);
+
+        list.add(root.val);
+        if (root.left == null && root.right == null && tar == currSum) {
+            ans.add(new ArrayList(list));
+        } else {
+            helper(root.left, currSum, list, tar);
+            helper(root.right, currSum, list, tar);
+        }
+        list.remove(list.size()-1);
+    }
+
+}

SymmetricTree.java

@@ -0,0 +1,17 @@
+public class SymmetricTree {
+    // Time Complexity : O(n)
+    // Space Complexity : O(h)
+    // Did this code successfully run on Leetcode : yes
+    public boolean isSymmetric(TreeNode root) {
+        if (root == null) return true;
+        return helper(root.left, root.right);
+    }
+
+    private boolean helper(TreeNode leftNode, TreeNode rightNode) {
+        if (leftNode == null && rightNode == null) return true;
+        if (leftNode == null || rightNode == null) return false;
+        if (leftNode.val != rightNode.val) return false;
+
+        return helper(leftNode.left, rightNode.right) && helper(leftNode.right, rightNode.left);
+    }
+}