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A binary watch has 4 LEDs on the top which represent the hours (0 11), and the 6 LEDs on the bottom represent the minutes (0 59). Each LED represents 阅读全文
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Given a string s and a string t, check if s is subsequence of t. You may assume that there is only lower case English letters in both s and t. t is po 阅读全文
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Given two strings s and t which consist of only lowercase letters. String t is generated by random shuffling string s and then add one more letter at 阅读全文
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Given a string, find the first non repeating character in it and return it’s index. If it doesn’t exist, return 1. Examples: Note: You may assume the 阅读全文
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Given an arbitrary ransom note string and another string containing letters from all the magazines, write a function that will return true if the rans 阅读全文
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You are given a list of non negative integers, a1, a2, …, an, and a target, S. Now you have 2 symbols + and . For each integer, you should choose one 阅读全文
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Given an integer array with all positive numbers and no duplicates, find the number of possible combinations that add up to a positive integer target. 阅读全文
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A sequence of numbers is called a wiggle sequence if the differences between successive numbers strictly alternate between positive and negative. The 阅读全文
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We are playing the Guess Game. The game is as follows: I pick a number from 1 to n. You have to guess which number I picked. Every time you guess wron 阅读全文
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Calculate the sum of two integers a and b, but you are not allowed to use the operator + and . Example: Given a = 1 and b = 2, return 3. 阅读全文
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Given a set of distinct positive integers, find the largest subset such that every pair (Si, Sj) of elements in this subset satisfies: Si % Sj = 0 or 阅读全文
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Given a non negative integer n, count all numbers with unique digits, x, where 0 ≤ x Given n = 2, return 91. (The answer should be the total numbers i 阅读全文
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Given two arrays, write a function to compute their intersection. Example: Given nums1 = [1, 2, 2, 1], nums2 = [2, 2], return [2, 2]. Note: + Each ele 阅读全文
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Given two arrays, write a function to compute their intersection. Example: Given nums1 = [1, 2, 2, 1], nums2 = [2, 2], return [2]. Note: + Each elemen 阅读全文
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Write a function that takes a string as input and returns the string reversed. Example: Given s = “hello”, return “olleh”. 分析 Easy 阅读全文
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Given a positive integer n, break it into the sum of at least two positive integers and maximize the product of those integers. Return the maximum pro 阅读全文
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Given a non negative integer number num. For every numbers i in the range 0 ≤ i ≤ num calculate the number of 1’s in their binary representation and r 阅读全文
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You are given coins of different denominations and a total amount of money amount. Write a function to compute the fewest number of coins that you nee 阅读全文
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Say you have an array for which the ith element is the price of a given stock on day i. Design an algorithm to find the maximum profit. You may comple 阅读全文
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Given a 2D matrix matrix, find the sum of the elements inside the rectangle defined by its upper left corner (row1, col1) and lower right corner (row2 阅读全文