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Given an unsorted integer array, find the smallest missing positive integer. Example 1: Example 2: Example 3: Note: Your algorithm should run in O(n) 阅读全文
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Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations in candidates where the candidate numb 阅读全文
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Given a set of candidate numbers (candidates) (without duplicates) and a target number (target), find all unique combinations in candidates where the 阅读全文
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The count-and-say sequence is the sequence of integers with the first five terms as following: 1 is read off as "one 1" or 11.11 is read off as "two 1 阅读全文
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Write a program to solve a Sudoku puzzle by filling the empty cells. A sudoku solution must satisfy all of the following rules: Empty cells are indica 阅读全文
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Determine if a 9x9 Sudoku board is valid. Only the filled cells need to be validated according to the following rules: A partially filled sudoku which 阅读全文
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Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in or 阅读全文
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Given an array of integers nums sorted in ascending order, find the starting and ending position of a given target value. Your algorithm's runtime com 阅读全文
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Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand. (i.e., [0,1,2,4,5,6,7] might become [4,5,6,7,0,1,2]). Y 阅读全文
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Given a string containing just the characters '(' and ')', find the length of the longest valid (well-formed) parentheses substring. Example 1: Exampl 阅读全文
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Implement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers. If such arrangement is not possib 阅读全文
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You are given a string, s, and a list of words, words, that are all of the same length. Find all starting indices of substring(s) in s that is a conca 阅读全文
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Given two integers dividend and divisor, divide two integers without using multiplication, division and mod operator. Return the quotient after dividi 阅读全文
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Implement strStr(). Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack. Example 1: Example 2: Cla 阅读全文
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Given an array nums and a value val, remove all instances of that value in-placeand return the new length. Do not allocate extra space for another arr 阅读全文
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Given a sorted array nums, remove the duplicates in-place such that each element appear only once and return the new length. Do not allocate extra spa 阅读全文
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Given a linked list, reverse the nodes of a linked list k at a time and return its modified list. k is a positive integer and is less than or equal to 阅读全文
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Given a linked list, swap every two adjacent nodes and return its head. Example: Note: Your algorithm should use only constant extra space. You may no 阅读全文
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Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. Example: 1 struct cmp { 2 bool operator () (ListNod 阅读全文
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Given n pairs of parentheses, write a function to generate all combinations of well-formed parentheses. For example, given n = 3, a solution set is: 1 阅读全文