随笔分类 - LeetCode
摘要：题意 Implement pow(x, n). 求X的N次方。 解法 用正常的办法来做是会超时的，因为可能有21亿次方的情况，所以需要优化一下。这里用到了 算法，简单来说就是将指数分解成二进制的形式，比如X的7次方，就可以表示成 ，这里将7分解成了 的形式，这样做之后，乘法就只需要进行三次，所以要做
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摘要：题意 Given a collection of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. Each
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摘要：题意 Given a set of candidate numbers (C) and a target number (T), find all unique combinations in C where the candidate numbers sums to T. The same rep
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摘要：题意 The count and say sequence is the sequence of integers beginning as follows: 1, 11, 21, 1211, 111221, ... 1 is read off as "one 1" or 11. 11 is rea
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摘要：题意 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
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摘要：题意 Given a sorted array of integers, find the starting and ending position of a given target value. Your algorithm's runtime complexity must be in the
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摘要：题意 Implement next permutation, which rearranges numbers into the lexicographically next greater permutation of numbers. If such arrangement is not pos
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摘要：题意 Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. 将K个排好序的链表合并成一个 解法 和之前合并两个有序链表那题不同，那题用的是两个指针来分别记录
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摘要：题意 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
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摘要：题意 Given an array S of n integers, are there elements a, b, c, and d in S such that a + b + c + d = target? Find all unique quadruplets in the array w
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摘要：题意 Given a digit string, return all possible letter combinations that the number could represent. A mapping of digit to letters (just like on the tele
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摘要：题意 Given an array S of n integers, find three integers in S such that the sum is closest to a given number, target. Return the sum of the three intege
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摘要：题意 Given an array S of n integers, are there elements a, b, c in S such that a + b + c = 0? Find all unique triplets in the array which gives the sum
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摘要：题意 Given n non negative integers a1, a2, ..., an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two en
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摘要：题意 Given a string, find the length of the longest substring without repeating characters. For example, the longest substring without repeating letters
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