81 - 每日算法题: Count Number of Unival Subtrees - count-number-of-unival-subtrees.txt.txt

Hi, here's your problem today. This problem was recently asked by Microsoft:

A unival tree is a tree where all the nodes have the same value. Given a binary tree, return the number of unival subtrees in the tree.

For example, the following tree should return 5:
...
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Top | 类别: 计算机科学 | 评论 (0) | 标签: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | 英文 | 78101 次阅读, 27558 次搜索 | 135 个单词

82 - 每日算法题: Longest Substring With K Distinct Characters - longest-substring-with-k-distinct-characters.txt.txt

Hi, here's your problem today. This problem was recently asked by Amazon:

You are given a string s, and an integer k. Return the length of the longest substring in s that contains at most k distinct characters.

For instance, given the string:
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Top | 类别: 计算机科学 | 评论 (0) | 标签: 每日算法题, Longest Substring With K Distinct Characters算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | 英文 | 76018 次阅读, 42024 次搜索 | 94 个单词

83 - 微信拉黑和删除有啥区别？ - wechat-block.txt.txt

相信很多使用微信的读者都曾经拉黑过某人，更不用说删除好友了，虽然拉黑和删除都能起到拒绝接收对方信息的效果，但它们具体有什么异同呢？拉黑和删除之后，还可以收发消息吗？聊天记录还在吗？还可以重新添加吗？对方知道自己被我拉黑/删除吗？

为了解答这个困扰良久的未解之谜，12月4日，腾讯微信团队官微在微博科普了拉黑与删除的区别。

问：还可以收发信息吗?
...
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Top | 类别: 计算机科学 | 评论 (0) | 标签: 微信, 拉黑, 删除, 区别, Wechat, Block, | 中文 | 88859 次阅读, 26407 次搜索 | 356 个汉字

84 - 每日算法题: Get all Values at a Certain Height in a Binary Tree - get-all-values-at-a-certain-height-in-a-binary-tree.txt.txt

Hi, here's your problem today. This problem was recently asked by Amazon:

Given a binary tree, return all values given a certain height h.

Here's a starting point:
...
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Top | 类别: 计算机科学 | 评论 (0) | 标签: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | 英文 | 75703 次阅读, 62341 次搜索 | 81 个单词

85 - 每日算法题: Validate Binary Search Tree - validate-binary-search-tree.txt.txt

Hi, here's your problem today. This problem was recently asked by Facebook:

You are given the root of a binary search tree. Return true if it is a valid binary search tree, and false otherwise. Recall that a binary search tree has the property that all values in the left subtree are less than or equal to the root, and all values in the right subtree are greater than or equal to the root.

Here's a starting point:
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Top | 类别: 计算机科学 | 评论 (0) | 标签: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | 英文 | 65197 次阅读, 25317 次搜索 | 128 个单词

86 - 每日算法题: First Missing Positive Integer - first-missing-positive-integer.txt

Hi, here's your problem today. This problem was recently asked by Facebook:

You are given an array of integers. Return the smallest positive integer that is not present in the array. The array may contain duplicate entries.

For example, the input [3, 4, -1, 1] should return 2 because it is the smallest positive integer that doesn't exist in the array.
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Top | 类别: 计算机科学 | 评论 (0) | 标签: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | 英文 | 78659 次阅读, 34963 次搜索 | 89 个单词

87 - 每日算法题: Look and Say Sequence - look-and-say-sequence.txt

Hi, here's your problem today. This problem was recently asked by Google:

A look-and-say sequence is defined as the integer sequence beginning with a single digit in which the next term is obtained by describing the previous term. An example is easier to understand:

Each consecutive value describes the prior value.
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Top | 类别: 计算机科学 | 评论 (0) | 标签: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | 英文 | 77187 次阅读, 25429 次搜索 | 77 个单词

88 - 每日算法题: Deepest Node in a Binary Tree - deepest-node-in-a-binary-tree.txt

Hi, here's your problem today. This problem was recently asked by Google:

You are given the root of a binary tree. Return the deepest node (the furthest node from the root).

Example:
...
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Top | 类别: 计算机科学 | 评论 (0) | 标签: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | 英文 | 79205 次阅读, 36103 次搜索 | 106 个单词

89 - 每日算法题: Buddy Strings - buddy-strings.txt

Hi, here's your problem today. This problem was recently asked by AirBNB:

Given two strings A and B of lowercase letters, return true if and only if we can swap two letters in A so that the result equals B.

Example 1:
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Top | 类别: 计算机科学 | 评论 (0) | 标签: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | 英文 | 79200 次阅读, 26275 次搜索 | 109 个单词

90 - 每日算法题: Trapping Rainwater - tapping-rainwater.txt

Hi, here's your problem today. This problem was recently asked by Uber:

You have a landscape, in which puddles can form. You are given an array of non-negative integers representing the elevation at each location. Return the amount of water that would accumulate if it rains.

For example: [0,1,0,2,1,0,1,3,2,1,2,1] should return 6 because 6 units of water can get trapped here.
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Top | 类别: 计算机科学 | 评论 (0) | 标签: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | 英文 | 77548 次阅读, 25141 次搜索 | 85 个单词

91 - 每日算法题: Create a balanced binary search tree - create-a-balanced-binary-search-tree.txt

Hi, here's your problem today. This problem was recently asked by LinkedIn:

Given a sorted list of numbers, change it into a balanced binary search tree. You can assume there will be no duplicate numbers in the list.

Here's a starting point:
...
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Top | 类别: 计算机科学 | 评论 (0) | 标签: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | 英文 | 63549 次阅读, 39693 次搜索 | 111 个单词

92 - 每日算法题: Merge K Sorted Linked Lists - merge-k-sorted-linked-list.txt

Hi, here's your problem today. This problem was recently asked by Twitter:

You are given an array of k sorted singly linked lists. Merge the linked lists into a single sorted linked list and return it.

Here's your starting point:
...
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Top | 类别: 计算机科学 | 评论 (0) | 标签: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | 英文 | 77408 次阅读, 30633 次搜索 | 98 个单词

93 - 每日算法题: Contiguous Subarray with Maximum Sum - contiguous-subarray-with-maximum-sum.txt

Hi, here's your problem today. This problem was recently asked by Twitter:

You are given an array of integers. Find the maximum sum of all possible contiguous subarrays of the array.

Example:
...
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Top | 类别: 计算机科学 | 评论 (0) | 标签: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | 英文 | 78479 次阅读, 34827 次搜索 | 80 个单词

94 - 每日算法题: Queue Using Two Stacks - queue-using-two-stacks.txt

Hi, here's your problem today. This problem was recently asked by Apple:

Implement a queue class using two stacks. A queue is a data structure that supports the FIFO protocol (First in = first out). Your class should support the enqueue and dequeue methods like a standard queue.

Here's a starting point:
...
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Top | 类别: 计算机科学 | 评论 (0) | 标签: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | 英文 | 79236 次阅读, 38127 次搜索 | 93 个单词

95 - 每日算法题: Maximum Profit From Stocks - maximum-profit-from-stocks.txt

Hi, here's your problem today. This problem was recently asked by Apple:

You are given an array. Each element represents the price of a stock on that particular day. Calculate and return the maximum profit you can make from buying and selling that stock only once.

For example: [9, 11, 8, 5, 7, 10]
...
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Top | 类别: 计算机科学 | 评论 (0) | 标签: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | 英文 | 77993 次阅读, 23435 次搜索 | 92 个单词

96 - 每日算法题: Merge Overlapping Intervals - merge-overlapping-intervals.txt

Hi, here's your problem today. This problem was recently asked by Microsoft:

You are given an array of intervals - that is, an array of tuples (start, end). The array may not be sorted, and could contain overlapping intervals. Return another array where the overlapping intervals are merged.

For example:
...
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Top | 类别: 计算机科学 | 评论 (0) | 标签: 每日算法题, 算法, 数据结构, 面试题, Daily Interview Problem, Data Structures and Algorithms, Computer Programming, Python, | 英文 | 78764 次阅读, 29328 次搜索 | 76 个单词