Add solution #655

Author: JoshCrozier

0655-print-binary-tree.js

@@ -0,0 +1,54 @@
+/**
+ * 655. Print Binary Tree
+ * https://leetcode.com/problems/print-binary-tree/
+ * Difficulty: Medium
+ *
+ * Given the root of a binary tree, construct a 0-indexed m x n string matrix res that represents
+ * a formatted layout of the tree. The formatted layout matrix should be constructed using the
+ * following rules:
+ * - The height of the tree is height and the number of rows m should be equal to height + 1.
+ * - The number of columns n should be equal to 2height+1 - 1.
+ * - Place the root node in the middle of the top row (more formally, at location res[0][(n-1)/2]).
+ * - For each node that has been placed in the matrix at position res[r][c], place its left child at
+ *   res[r+1][c-2height-r-1] and its right child at res[r+1][c+2height-r-1].
+ * - Continue this process until all the nodes in the tree have been placed.
+ * - Any empty cells should contain the empty string "".
+ *
+ * Return the constructed matrix res.
+ */
+
+/**
+ * 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 {string[][]}
+ */
+var printTree = function(root) {
+  const height = getHeight(root);
+  const columns = Math.pow(2, height + 1) - 1;
+  const result = new Array(height + 1).fill().map(() => {
+    return new Array(columns).fill('');
+  });
+
+  fill(root, 0, Math.floor((columns - 1) / 2), height);
+
+  return result;
+
+  function fill(node, r, c, h) {
+    if (!node) return;
+    result[r][c] = node.val.toString();
+    fill(node.left, r + 1, c - Math.pow(2, h - r - 1), h);
+    fill(node.right, r + 1, c + Math.pow(2, h - r - 1), h);
+  }
+
+  function getHeight(node) {
+    if (!node) return -1;
+    return 1 + Math.max(getHeight(node.left), getHeight(node.right));
+  }
+};

README.md

@@ -493,6 +493,7 @@
 652|[Find Duplicate Subtrees](./0652-find-duplicate-subtrees.js)|Medium|
 653|[Two Sum IV - Input is a BST](./0653-two-sum-iv-input-is-a-bst.js)|Easy|
 654|[Maximum Binary Tree](./0654-maximum-binary-tree.js)|Medium|
+655|[Print Binary Tree](./0655-print-binary-tree.js)|Medium|
 680|[Valid Palindrome II](./0680-valid-palindrome-ii.js)|Easy|
 684|[Redundant Connection](./0684-redundant-connection.js)|Medium|
 686|[Repeated String Match](./0686-repeated-string-match.js)|Easy|