Create 1530-number-of-good-leaf-nodes-pairs.js

Author: everthis

1530-number-of-good-leaf-nodes-pairs.js

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+/**
+ * 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} distance
+ * @return {number}
+ */
+const countPairs = function(root, distance) {
+  let res = 0
+  traverse(root)
+  return res
+  
+  
+  function traverse(node) {
+    if(node == null) return []
+    if(node.left == null && node.right == null) return [0]
+    
+    const left = traverse(node.left)
+    const right = traverse(node.right)
+    for(let i = 0; i < left.length; i++) {
+      for(let j = 0; j < right.length; j++) {
+        if(left[i] + right[j] + 2 <= distance) res++
+      }
+    }
+    
+    return [...left.map(e => e + 1), ...right.map(e => e + 1)]
+  }
+};