James Pan

原题网址：https://leetcode.com/problems/implement-queue-using-stacks/ mplement the following operations of a queue using stacks. push(x) -- Push element x to the back of queue.pop() -- Removes the

原题网址：https://www.hackerrank.com/challenges/matrix-rotation-algo You are given a 2D matrix, a, of dimension MxN and a positive integer R. You have to rotate the matrix R times and print th

原题网址：https://leetcode.com/problems/wiggle-sort-ii/ Given an unsorted array nums, reorder it such that nums[0] nums[2] . Example: (1) Given nums = [1, 5, 1, 1, 6, 4], one possible answer is

原题网址：https://leetcode.com/problems/rotate-image/ You are given an n x n 2D matrix representing an image. Rotate the image by 90 degrees (clockwise). Follow up: Could you do this in-place?

原题网址：https://leetcode.com/problems/swap-nodes-in-pairs/ Given a linked list, swap every two adjacent nodes and return its head. For example, Given 1->2->3->4, you should return the list as 2-

原题网址：https://leetcode.com/submissions/detail/58253344/ Given a singly linked list, determine if it is a palindrome. Follow up: Could you do it in O(n) time and O(1) space? 思路：普通的思路是可以生成一个反转的

原题网址：https://leetcode.com/problems/invert-binary-tree/ Invert a binary tree. 4 / \ 2 7 / \ / \ 1 3 6 9 to 4 / \ 7 2 / \ / \ 9 6 3 1 思路：递归调用，对左右子节

原题网址：https://leetcode.com/problems/reorder-list/ Given a singly linked list L: L0→L1→…→Ln-1→Ln, reorder it to: L0→Ln→L1→Ln-1→L2→Ln-2→… You must do this in-place without altering the nodes' va

原题网址：https://leetcode.com/problems/find-minimum-in-rotated-sorted-array/ Suppose a sorted array is rotated at some pivot unknown to you beforehand. (i.e., 0 1 2 4 5 6 7 might become 4 5 6 7

原题网址：https://leetcode.com/problems/flatten-binary-tree-to-linked-list/ Given a binary tree, flatten it to a linked list in-place. For example, Given 1 / \ 2 5

原题网址：https://leetcode.com/problems/binary-tree-upside-down/ Given a binary tree where all the right nodes are either leaf nodes with a sibling (a left node that shares the same parent node) or em