xiaoyongyong

摘要： redis 安装： brew install redis 启动redis： /usr/local/opt/redis/bin/redis-server /usr/local/etc/redis.conf 进入redis： redis-cli String 127.0.0.1:6379> 127.0. 阅读全文

摘要： 1.简单的加减问题，比如：1+2-3=0 1+2-3 可以看作 +1+2-3 ， 那么我们可以逐个把这些数字放到stack，最后加起来 class Solution { public int calculate(String s) { Stack<Integer> stack = new Stack 阅读全文

摘要： 203. Remove Linked List Elements Easy Given the head of a linked list and an integer val, remove all the nodes of the linked list that has Node.val == 阅读全文

摘要： 206. Reverse Linked List Easy 9329166Add to ListShare Given the head of a singly linked list, reverse the list, and return the reversed list. Example 阅读全文

摘要： 206. Reverse Linked List Easy Given the head of a singly linked list, reverse the list, and return the reversed list. Example 1: Input: head = [1,2,3, 阅读全文

摘要： 1254. Number of Closed Islands Medium Given a 2D grid consists of 0s (land) and 1s (water). An island is a maximal 4-directionally connected group of  阅读全文

摘要： 547. Number of Provinces Medium There are n cities. Some of them are connected, while some are not. If city a is connected directly with city b, and c 阅读全文

摘要： 208. Implement Trie (Prefix Tree) Medium A trie (pronounced as "try") or prefix tree is a tree data structure used to efficiently store and retrieve k 阅读全文

摘要： 239. Sliding Window Maximum Hard You are given an array of integers nums, there is a sliding window of size k which is moving from the very left of th 阅读全文

摘要： 496. Next Greater Element I The next greater element of some element x in an array is the first greater element that is to the right of x in the same 阅读全文