Add solution #1457

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,311 LeetCode solutions in JavaScript
+# 1,312 LeetCode solutions in JavaScript
 
 [https://leetcodejavascript.com](https://leetcodejavascript.com)
 
@@ -1113,6 +1113,7 @@
 1453|[Maximum Number of Darts Inside of a Circular Dartboard](./solutions/1453-maximum-number-of-darts-inside-of-a-circular-dartboard.js)|Hard|
 1455|[Check If a Word Occurs As a Prefix of Any Word in a Sentence](./solutions/1455-check-if-a-word-occurs-as-a-prefix-of-any-word-in-a-sentence.js)|Easy|
 1456|[Maximum Number of Vowels in a Substring of Given Length](./solutions/1456-maximum-number-of-vowels-in-a-substring-of-given-length.js)|Medium|
+1457|[Pseudo-Palindromic Paths in a Binary Tree](./solutions/1457-pseudo-palindromic-paths-in-a-binary-tree.js)|Medium|
 1460|[Make Two Arrays Equal by Reversing Sub-arrays](./solutions/1460-make-two-arrays-equal-by-reversing-sub-arrays.js)|Easy|
 1462|[Course Schedule IV](./solutions/1462-course-schedule-iv.js)|Medium|
 1464|[Maximum Product of Two Elements in an Array](./solutions/1464-maximum-product-of-two-elements-in-an-array.js)|Easy|

solutions/1457-pseudo-palindromic-paths-in-a-binary-tree.js

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+/**
+ * 1457. Pseudo-Palindromic Paths in a Binary Tree
+ * https://leetcode.com/problems/pseudo-palindromic-paths-in-a-binary-tree/
+ * Difficulty: Medium
+ *
+ * Given a binary tree where node values are digits from 1 to 9. A path in the binary tree
+ * is said to be pseudo-palindromic if at least one permutation of the node values in the
+ * path is a palindrome.
+ *
+ * Return the number of pseudo-palindromic paths going from the root node to leaf nodes.
+ */
+
+/**
+ * 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 pseudoPalindromicPaths = function(root) {
+  const frequency = new Array(10).fill(0);
+  let count = 0;
+
+  traverse(root);
+
+  return count;
+
+  function traverse(node) {
+    if (!node) return;
+
+    frequency[node.val]++;
+
+    if (!node.left && !node.right) {
+      let oddCount = 0;
+      for (let i = 1; i <= 9; i++) {
+        if (frequency[i] % 2 !== 0) oddCount++;
+      }
+      if (oddCount <= 1) count++;
+    }
+
+    traverse(node.left);
+    traverse(node.right);
+
+    frequency[node.val]--;
+  }
+};