solves #113 in java

Author: anishLearnsToCode

Diff for: README.md

@@ -105,7 +105,7 @@
 | 110  | [Balanced Binary Tree](https://leetcode.com/problems/balanced-binary-tree)                                                                                |                                [![Java](assets/java.png)](src/BalancedBinaryTree.java) [![Python](assets/python.png)](python/balanced_binary_tree.py)                                |                                                                                                                                   |
 | 111  | [Minimum Depth of Binary Tree](https://leetcode.com/problems/minimum-depth-of-binary-tree)                                                                |                         [![Java](assets/java.png)](src/MinimumDepthOfBinaryTree.java) [![Python](assets/python.png)](python/minimum_depth_of_binary_tree.py)                         |                                                                                                                                   |
 | 112  | [Path Sum](https://leetcode.com/problems/path-sum)                                                                                                        |                                           [![Java](assets/java.png)](src/PathSum.java) [![Python](assets/python.png)](python/path_sum.py)                                            |                                                                                                                                   |
-| 113  | [Path Sum II](https://leetcode.com/problems/path-sum-ii)                                                                                                  |                                                                                                                                                                                      |                                                                                                                                   |
+| 113  | [Path Sum II](https://leetcode.com/problems/path-sum-ii)                                                                                                  |                                                                    [![Java](assets/java.png)](src/PathSumII.java)                                                                    |                                                                                                                                   |
 | 114  | [Flatten Binary Tree to Linked List](https://leetcode.com/problems/flatten-binary-tree-to-linked-list)                                                    |                                                                                                                                                                                      |                                                                                                                                   |
 | 116  | [Populating Next Right Pointers in Each Node](https://leetcode.com/problems/populating-next-right-pointers-in-each-node)                                  |                                                                                                                                                                                      |                                                                                                                                   |
 | 117  | [Populating Next Right Pointers in Each Node II](https://leetcode.com/problems/populating-next-right-pointers-in-each-node-ii)                            |                                                                                                                                                                                      |                                                                                                                                   |

Diff for: src/PathSumII.java

@@ -0,0 +1,43 @@
+// https://leetcode.com/problems/path-sum-ii
+// T: O(n * log(n))
+// S: O(n * log(n))
+
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+
+public class PathSumII {
+    public List<List<Integer>> pathSum(TreeNode root, int targetSum) {
+        final List<List<Integer>> result = new ArrayList<>();
+        if (root == null) return result;
+        pathSum(root, targetSum, result);
+        return result;
+    }
+
+    private void pathSum(TreeNode root, int targetSum, final List<List<Integer>> result) {
+        pathSum(root, targetSum, result, 0, new LinkedList<>());
+    }
+
+    private void pathSum(TreeNode root, int targetSum, final List<List<Integer>> result, int sum, LinkedList<Integer> path) {
+        path.addLast(root.val);
+        sum += root.val;
+
+        if (isLeafNode(root)) {
+            if (sum == targetSum) result.add(new ArrayList<>(path));
+            return;
+        }
+
+        if (root.left != null) {
+            pathSum(root.left, targetSum, result, sum, path);
+            path.removeLast();
+        }
+        if (root.right != null) {
+            pathSum(root.right, targetSum, result, sum, path);
+            path.removeLast();
+        }
+    }
+
+    private boolean isLeafNode(TreeNode root) {
+        return root.left == null && root.right == null;
+    }
+}