Given an array of integers, find if the array contains any duplicates. Your function should return true if any value appears at least twice in the array, and it should return false if every element is distinct. 第一种方法:set数据结构,count函数记录数是否出现过,耗时96ms 用数…

 217 - Contains Duplicate Given an array of integers, find if the array contains any duplicates. Your function should return true if any value appears at least twice in the array, and it should return false if every element is distinct. Solution 1: s…

原文题目: 217. Contains Duplicate 219. Contains Duplicate II 读题: 217只要找出是否有重复值, 219找出重复值,且要判断两者索引之差是否小于k //217. Contains Duplicate 46ms class Solution { public: bool containsDuplicate(vector<int>& nums) { set <int> s; //vector <int>::ite…

Problem Link: https://oj.leetcode.com/problems/binary-tree-level-order-traversal-ii/ Use BFS from the tree root to traverse the tree level by level. The python code is as follows. # Definition for a binary tree node # class TreeNode: # def __init__(s…

Follow up for "Search in Rotated Sorted Array":What if duplicates are allowed? Would this affect the run-time complexity? How and why? Write a function to determine if a given target is in the array. 这个和前面的一个不一样就在于可能会有重复的数字,那么判断的时候就应该注意了,遇到start…

Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left to right, level by level from leaf to root). For example:Given binary tree {3,9,20,#,#,15,7}, 3 / \ 9 20 / \ 15 7 return its bottom-up level order tr…

Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list. For example,Given 1->2->3->3->4->4->5, return 1->2->5.Given 1->1->1->2->3, return 2->3.…

题目 Follow up for "Remove Duplicates": What if duplicates are allowed at most twice? For example, Given sorted array nums = [1,1,1,2,2,3], Your function should return length = 5, with the first five elements of nums being 1, 1, 2, 2 and 3. It doe…

Given a sorted linked list, delete all nodes that have duplicate numbers, leaving only distinct numbers from the original list. For example,Given 1->2->3->3->4->4->5, return 1->2->5.Given 1->1->1->2->3, return 2->3.…

Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order. For example,Given n = 3, You should return the following matrix: [ [ 1, 2, 3 ], [ 8, 9, 4 ], [ 7, 6, 5 ] ] 依旧是dfs问题,代码如下所示: class Solution { public: vecto…