Add solution #113

Author: JoshCrozier

README.md

@@ -106,6 +106,7 @@
 110|[Balanced Binary Tree](./0110-balanced-binary-tree.js)|Easy|
 111|[Minimum Depth of Binary Tree](./0111-minimum-depth-of-binary-tree.js)|Easy|
 112|[Path Sum](./0112-path-sum.js)|Easy|
+113|[Path Sum II](./0113-path-sum-ii.js)|Medium|
 116|[Populating Next Right Pointers in Each Node](./0116-populating-next-right-pointers-in-each-node.js)|Medium|
 118|[Pascal's Triangle](./0118-pascals-triangle.js)|Easy|
 119|[Pascal's Triangle II](./0119-pascals-triangle-ii.js)|Easy|

solutions/0113-path-sum-ii.js

@@ -0,0 +1,43 @@
+/**
+ * 113. Path Sum II
+ * https://leetcode.com/problems/path-sum-ii/
+ * Difficulty: Medium
+ *
+ * Given the root of a binary tree and an integer targetSum, return all root-to-leaf paths where
+ * the sum of the node values in the path equals targetSum. Each path should be returned as a
+ * list of the node values, not node references.
+ *
+ * A root-to-leaf path is a path starting from the root and ending at any leaf node. A leaf is a
+ * node with no children.
+ */
+
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @param {number} targetSum
+ * @return {number[][]}
+ */
+var pathSum = function(root, targetSum) {
+  if (!root) return [];
+  return traverse([], targetSum, root);
+};
+
+function traverse(result, targetSum, node, history = []) {
+  const values = [...history, node.val];
+
+  if (!node.left && !node.right && values.reduce((sum, n) => sum + n, 0) === targetSum) {
+    result.push(values);
+  }
+
+  if (node.left) traverse(result, targetSum, node.left, values);
+  if (node.right) traverse(result, targetSum, node.right, values);
+
+  return result;
+}