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摘要： Symmetric TreeGiven a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).For example, this binary tree is symmetric... 阅读全文

摘要： Balanced Binary TreeGiven a binary tree, determine if it is height-balanced.For this problem, a height-balanced binary tree is defined as a binary tre... 阅读全文

摘要： Wiggle Sort IIGiven an unsorted arraynums, reorder it such thatnums[0] nums[2] < nums[3]....Example:(1) Givennums = [1, 5, 1, 1, 6, 4], one possible ... 阅读全文

摘要： Contains Duplicate IIIGiven an array of integers, find out whether there are two distinct indicesiandjin the array such that the difference betweennum... 阅读全文

摘要： Coin ChangeYou are given coins of different denominations and a total amount of moneyamount. Write a function to compute the fewest number of coins th... 阅读全文

摘要： Create Maximum Number Given two arrays of length m and n with digits 0-9 representing two numbers. Create the maximum number of length k <= m + n from 阅读全文

摘要： Remove Duplicate LettersGiven a string which contains only lowercase letters, remove duplicate letters so that every letter appear once and only once.... 阅读全文

摘要： Maximum Product of Word LengthsGiven a string arraywords, find the maximum value oflength(word[i]) * length(word[j])where the two words do not share c... 阅读全文

摘要： Bulb SwitcherThere arenbulbs that are initially off. You first turn on all the bulbs. Then, you turn off every second bulb. On the third round, you to... 阅读全文

摘要： Word SearchGiven a 2D board and a word, find if the word exists in the grid.The word can be constructed from letters of sequentially adjacent cell, wh... 阅读全文