61 lines
1.6 KiB
JavaScript
61 lines
1.6 KiB
JavaScript
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/*
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* @lc app=leetcode id=108 lang=javascript
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*
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* [108] Convert Sorted Array to Binary Search Tree
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*
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* https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/description/
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*
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* algorithms
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* Easy (49.37%)
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* Total Accepted: 255.2K
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* Total Submissions: 507.2K
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* Testcase Example: '[-10,-3,0,5,9]'
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*
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* Given an array where elements are sorted in ascending order, convert it to a
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* height balanced BST.
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*
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* For this problem, a height-balanced binary tree is defined as a binary tree
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* in which the depth of the two subtrees of every node never differ by more
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* than 1.
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*
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* Example:
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*
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*
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* Given the sorted array: [-10,-3,0,5,9],
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*
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* One possible answer is: [0,-3,9,-10,null,5], which represents the following
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* height balanced BST:
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*
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* 0
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* / \
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* -3 9
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* / /
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* -10 5
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*
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*
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*/
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/**
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* Definition for a binary tree node.
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* function TreeNode(val) {
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* this.val = val;
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* this.left = this.right = null;
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* }
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*/
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/**
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* @param {number[]} nums
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* @return {TreeNode}
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*/
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var sortedArrayToBST = function(nums) {
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// 由于数组是排序好的，因此一个思路就是将数组分成两半，一半是左子树，另一半是右子树
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// 然后运用“树的递归性质”递归完成操作即可。
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if(nums.length === 0) return null;
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const mid = nums.length >> 1;
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const root = new TreeNode(nums[mid]);
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root.left = sortedArrayToBST(nums.slice(0, mid));
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root.right = sortedArrayToBST(nums.slice(mid + 1))
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return root;
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// 扩展： 这道题启示我们如果是一个非排序的数组，我们可以先进行排序然后再按上述思路进行。
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};
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