leetcode 解题思路

You are given an array of stringsnumsand an integerk. Each string innumsrepresents an integer without leading zeros.Returnthe string that represents thekthlargest integerinnums.Note: Duplicate numbers should be counted distinctly. For example...

Given somepointsand anoriginpoint in two-dimensional space, findkpoints which are nearest to theorigin.Return these points sorted by distance, if they are same in distance, sorted by the x-axi...

Merge k Sorted Lists(这题是用PQ，或者merge sort都可以做，关于第K大的问题，参考: PriorityQueue 第K大问题总结)Sort an Array ( 重点掌握merge sort和quick sort，因为两者可以演变为很多其他的算法,divide conquer, quick select)Merge IntervalsSort ColorsSort ListConvert Sorted Array to Binary Searc...

找第k大或者第k小的题型，也是经常面试考，这里做个总结；首先quick select算法的模板要倒背如流，这个是通过quick sort里面提炼得到的算法；两个while一个if，condition相同；后面再递归Kth Smallest Numbers in Unsorted Array找到一个无序数组中第K小的数Example样例 1:输入: [3, 4, 1, 2,...

Find K-th largest element in an array. and N is much larger than k. Note that it is the kth largest element in the sorted order, not the kth distinct element.ExampleExample 1:Input:[9,3,2,4,8],...

Given an array ofnobjects withkdifferent colors (numbered from 1 to k), sort them so that objects of the same color are adjacent, with the colors in the order 1, 2, ... k.ExampleExample1Inp...

Find K-th largest element in an array.ExampleExample 1:Input:n = 1, nums = [1,3,4,2]Output:4Example 2:Input:n = 3, nums = [9,3,2,4,8]Output:4ChallengeO(n) time, O(1) extra memo...

Given an integer array, sort it in ascending order. Use selection sort, bubble sort, insertion sort or any O(n2) algorithm.ExampleExample 1: Input: [3, 2, 1, 4, 5] Output: [1, 2, 3, 4, 5] E...

Given a set ofnnuts of different sizes andnbolts of different sizes. There is a one-one mapping between nuts and bolts.Comparison of a nut to another nut or a bolt to another bolt isnot allowed...

Find the kth smallest number in an unsorted integer array.ExampleExample 1:Input: [3, 4, 1, 2, 5], k = 3Output: 3Example 2:Input: [1, 1, 1], k = 2Output: 1ChallengeAn O(nlogn) algo...