05 2021 档案
摘要：Given an array arr of positive integers, consider all binary trees such that: Each node has either 0 or 2 children; The values of arr correspond to th
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摘要：Consider a directed graph, with nodes labelled 0, 1, ..., n-1. In this graph, each edge is either red or blue, and there could be self-edges or parall
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摘要：Given a list of dominoes, dominoes[i] = [a, b] is equivalent to dominoes[j] = [c, d] if and only if either (a==c and b==d), or (a==d and b==c) - that
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摘要：In a project, you have a list of required skills req_skills, and a list of people. The ith person people[i] contains a list of skills that the person
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摘要：We are given hours, a list of the number of hours worked per day for a given employee. A day is considered to be a tiring day if and only if the numbe
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摘要：Given two arrays arr1 and arr2, the elements of arr2 are distinct, and all elements in arr2 are also in arr1. Sort the elements of arr1 such that the
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摘要：博主在用 Hexo 搭建博客的时候，一直在考虑评论系统用什么，最终比较了多家，决定用 Gitalk，这是一个基于 Github Issues 的评论系统，所有的评论内容都保存在 Github Issues 中，每篇博客对应一个 Issues。只有登陆 Github 账号才能评论，大多数人应该都会有
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摘要：A string is a valid parentheses string (denoted VPS) if and only if it consists of "(" and ")" characters only, and: It is the empty string, or It can
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摘要：Given the root of a binary tree, each node in the tree has a distinct value. After deleting all nodes with a value in to_delete, we are left with a fo
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摘要：There are n flights that are labeled from 1 to n. You are given an array of flight bookings bookings, where bookings[i] = [firsti, lasti, seatsi] repr
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摘要：Given a valid (IPv4) IP address, return a defanged version of that IP address. A defanged IP address replaces every period "." with "[.]". Example 1:
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摘要：Return the result of evaluating a given boolean expression, represented as a string. An expression can either be: "t", evaluating to True; "f", evalua
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