Sort ColorsGiven 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 integers 0, 1, and 2 to represent the color red, wh…

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…

Sort a linked list in O(n log n) time using constant space complexity. 1.分析 该题主要考查了链接上的合并排序算法. 2.正确代码实现 package com.edu.leetcode; import com.edu.leetcode.ListNode; public class SortList { /** * @param args */ public ListNode Merge(ListNode first,List…

Sort a linked list in O(n log n) time using constant space complexity. 排序,要求是O(nlog(n))的时间复杂度和常数的空间复杂度,那么就使用归并就可以了. /** * Definition for singly-linked list. * public class ListNode { * int val; * ListNode next; * ListNode(int x) { val = x; } * } */ p…

Sort a linked list using insertion sort. 插入排序. /** * Definition for singly-linked list. * public class ListNode { * int val; * ListNode next; * ListNode(int x) { val = x; } * } */ public class Solution { public ListNode insertionSortList(ListNode hea…

Sort a linked list in O(n log n) time using constant space complexity. 常见排序方法有很多,插入排序,选择排序,堆排序,快速排序,冒泡排序,归并排序,桶排序等等..它们的时间复杂度不尽相同,而这里题目限定了时间必须为O(nlgn),符合要求只有快速排序,归并排序,堆排序,而根据单链表的特点,最适于用归并排序.代码如下: C++ 解法一: class Solution { public: ListNode* sortList(L…

Sort List Sort a linked list in O(n log n) time using constant space complexity. 使用Merge Sort, 空间复杂度是 O(logN) 因为使用了栈空间. SOLUTION 1: 使用Merge Sort来解决问题. 为什么不用QuickSort? 因为随机访问对于链表而言太耗时,而heap sort不可行. 注意,Find Mid用了2种解法.或者是让Fast提前结束,或是让Fast先走一步,目的就是要取得中间…

Given a string, sort it in decreasing order based on the frequency of characters. Example 1: Input: "tree" Output: "eert" Explanation: 'e' appears twice while 'r' and 't' both appear once. So 'e' must appear before both 'r' and 't'. Th…

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 integers 0, 1, and 2 to represent the color red, white, and bl…

整体思路同之前的一样,依然采取降低维度的方式进行 public List<List<Integer>> solution(int nums[], int target) { List<List<Integer>> result = new ArrayList<>(); if((nums.length<4)||(nums==null)) { return result; } Arrays.sort(nums); if ((4*nums[0]&…