Add solution #513

Author: JoshCrozier

README.md

@@ -409,6 +409,7 @@
 507|[Perfect Number](./0507-perfect-number.js)|Easy|
 508|[Most Frequent Subtree Sum](./0508-most-frequent-subtree-sum.js)|Medium|
 509|[Fibonacci Number](./0509-fibonacci-number.js)|Easy|
+513|[Find Bottom Left Tree Value](./0513-find-bottom-left-tree-value.js)|Medium|
 520|[Detect Capital](./0520-detect-capital.js)|Easy|
 521|[Longest Uncommon Subsequence I](./0521-longest-uncommon-subsequence-i.js)|Easy|
 530|[Minimum Absolute Difference in BST](./0530-minimum-absolute-difference-in-bst.js)|Easy|

solutions/0513-find-bottom-left-tree-value.js

@@ -0,0 +1,36 @@
+/**
+ * 513. Find Bottom Left Tree Value
+ * https://leetcode.com/problems/find-bottom-left-tree-value/
+ * Difficulty: Medium
+ *
+ * Given the root of a binary tree, return the leftmost value in the last row of the tree.
+ */
+
+/**
+ * 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
+ * @return {number}
+ */
+var findBottomLeftValue = function(root) {
+  const queue = [root];
+  let result = root.val;
+
+  while (queue.length) {
+    const size = queue.length;
+    result = queue[0].val;
+    for (let i = 0; i < size; i++) {
+      const node = queue.shift();
+      if (node.left) queue.push(node.left);
+      if (node.right) queue.push(node.right);
+    }
+  }
+
+  return result;
+};