原题地址:https://oj.leetcode.com/problems/sort-colors/ 题意: Given an array with n objects colored red, white or blue, sort them so that objects of the same color are adjacent, with the colors in the order red, white and blue. Here, we will use the integer…

原题地址:http://oj.leetcode.com/problems/sort-list/ 题意:链表的排序.要求:时间复杂度O(nlogn),空间复杂度O(1). 解题思路:由于题目对时间复杂度和空间复杂度要求比较高,所以查看了各种解法,最好的解法就是归并排序,由于链表在归并操作时并不需要像数组的归并操作那样分配一个临时数组空间,所以这样就是常数空间复杂度了,当然这里不考虑递归所产生的系统调用的栈.   这里涉及到一个链表常用的操作,即快慢指针的技巧.设置slow和fast指针,开始它们都…

LeetCode--Sort List Question Sort a linked list in O(n log n) time using constant space complexity. Solution 看到对链表的排序,时间复杂度O(n log n),首先想到的就是归并排序. 但是这里其中有两个技巧: 就是将两个链表分开的时候,用到了fast-slow法,这是在处理链表分治,也就是找中间节点的一种有效方法. 还有就是merge的过程,也用到了递归的方式. Code /** * D…

题目来源: https://leetcode.com/problems/insertion-sort-list/ 题意分析: 用插入排序排序一个链表. 题目思路: 这题没什么好说的,直接用插入排序就行. 代码(python): # Definition for singly-linked list. # class ListNode(object): # def __init__(self, x): # self.val = x # self.next = None class Solution…

原题地址:http://oj.leetcode.com/problems/insertion-sort-list/ 题意:对链表进行插入排序. 解题思路:首先来对插入排序有一个直观的认识,来自维基百科. 代码循环部分图示: 代码: class Solution: # @param head, a ListNode # @return a ListNode def insertionSortList(self, head): if not head: return head dummy = Lis…

题目来源 https://leetcode.com/problems/subsets-ii/ Given a collection of integers that might contain duplicates, nums, return all possible subsets. Note: Elements in a subset must be in non-descending order. The solution set must not contain duplicate su…

题目来源 https://leetcode.com/problems/subsets/ Given a set of distinct integers, nums, return all possible subsets. Note: Elements in a subset must be in non-descending order. The solution set must not contain duplicate subsets. 题意分析 Input: :type nums:…

题目来源 https://leetcode.com/problems/anagrams/ Given an array of strings, group anagrams together. For example, given: ["eat", "tea", "tan", "ate", "nat", "bat"], Return: [ ["ate", "…

题目来源 https://leetcode.com/problems/permutations-ii/ Given a collection of numbers that might contain duplicates, return all possible unique permutations. For example,[1,1,2] have the following unique permutations:[1,1,2], [1,2,1], and [2,1,1]. 题意分析In…

题目来源 https://leetcode.com/problems/insert-interval/ Given a set of non-overlapping intervals, insert a new interval into the intervals (merge if necessary). You may assume that the intervals were initially sorted according to their start times. Examp…