128. 最长连续序列 给定一个未排序的整数数组,找出最长连续序列的长度. 要求算法的时间复杂度为 O(n). 示例: 输入: [100, 4, 200, 1, 3, 2] 输出: 4 解释: 最长连续序列是 [1, 2, 3, 4].它的长度为 4. class Solution { public int longestConsecutive(int[] nums) { Set<Integer> numsSet = new HashSet<>(); for (Integer nu…

前言: 每道题附带动态示意图,提供java.python两种语言答案,力求提供leetcode最优解. 描述: 给定一个未排序的整数数组,找出最长连续序列的长度. 要求算法的时间复杂度为 O(n). 示例: 输入: [100, 4, 200, 1, 3, 2]输出: 4解释: 最长连续序列是 [1, 2, 3, 4].它的长度为 4. 思路: 首先,我们先来看一个简单的例子:序列123 序列 56,插入4,求连续序列长度. 很容易得出结论,答案是6,那么这个6是怎么来的呢?6 = len(1,2…

题目描述 给定一个未排序的整数数组,找出最长连续序列的长度. 要求算法的时间复杂度为 O(n). 示例: 输入: [100, 4, 200, 1, 3, 2] 输出: 4 解释: 最长连续序列是 [1, 2, 3, 4].它的长度为 4. 解题思路 利用并查集的思想,构造一个map记录数组中以每个数所在的最长连续序列长度.每次遍历到一个数时,首先检查map中是否存在该数,若存在直接跳过,否则作如下更新操作: 找到左右相邻数字是否在map中,若存在则分别记录他们所在的最长连续序列长度,并更新当前的…

方法一:使用快排: //排序法,时间O(nlogn),使用STL,只是验证一下思想,非正解: class Solution { public: int longestConsecutive(vector<int>& nums) { sort(nums.begin(),nums.end()); ; ;i<nums.size();i++){ ,len=; &&nums[i+step+]-nums[i+step]<=){ ==nums[i+step+]) len+…

题目 给定一个未排序的整数数组,找出最长连续序列的长度. 要求算法的时间复杂度为O(n). 示例: 输入:[100, 4, 200, 1, 3, 2] 输出:4 解释:最长连续序列是[1, 2, 3, 4].它的长度为4 思路 思路一 先由小到大进行排序 考虑三种情况: 前后相差1,则是连续序列 前后相等,循环continue 最后一个元素,break 代码 def longestConsecutive(nums) -> int:     if nums:         nums.sort()…

1. 具体题目 给定一个未排序的整数数组,找出最长连续序列的长度.要求算法的时间复杂度为 O(n). 示例: 输入: [100, 4, 200, 1, 3, 2] 输出: 4 解释: 最长连续序列是 [1, 2, 3, 4].它的长度为 4. 2. 思路分析 由于题目中不要求连续序列中的元素在原数组中是有序的,对于一个数只要查找数组中是否有与其相邻的数即可,所以考虑将元素存入HashSet中,实现 O(1)时间的查询. 3. 代码 public int longestConsecutive(in…

题目描述: 给定一个未排序的整数数组,找出最长连续序列的长度. 要求算法的时间复杂度为 O(n). 示例: 输入:[100, 4, 200, 1, 3, 2] 输出:4 即最长的连续序列为 [1,2,3,4] 思路分析: 由于要求O(n)的复杂读,因此直接排序是不可行的. 这里用到的是并查集的思想.对于每一个数,去查小于1和大于1的数是否在序列中.通过迭代求解. 尽管在 for 循环中嵌套了一个 while 循环,时间复杂度看起来像是二次方级别的.但其实它是线性的算法.因为只有当 current…

给定一个未排序的整数数组,找出最长连续序列的长度. 要求算法的时间复杂度为 O(n). 示例: 输入: [100, 4, 200, 1, 3, 2]输出: 4解释: 最长连续序列是 [1, 2, 3, 4].它的长度为 4. 暴力超时... class Solution: def longestConsecutive(self, nums: List[int]) -> int: longestSequence = 0 for num in nums: curNum = num streak =…

[问题]给定一个未排序的整数数组,找出最长连续序列的长度. 要求算法的时间复杂度为 O(n). 示例: 输入: [, , , , , ] 输出: 解释: 最长连续序列是 [, , , ].它的长度为 . [思路] 首先使用一个哈希set将我们的数据全都保存,然后遍历整个数组,假如遍历到了数字A,其一定在哈希set中,这是毋庸置疑的.接着我们需要进入一个while循环去判断A+1,A+2,A+3…是不是也在这个哈希表中,如果尝试到数字B,其不在哈希表中则退出,此时最长连续序列B-A. 既然我们查找…

Given an unsorted array of integers, find the length of the longest consecutive elements sequence. For example,Given [100, 4, 200, 1, 3, 2],The longest consecutive elements sequence is [1, 2, 3, 4]. Return its length: 4. Your algorithm should run in…

Given an unsorted array of integers, find the length of the longest consecutive elements sequence. Your algorithm should run in O(n) complexity. Example: Input: [100, 4, 200, 1, 3, 2] Output: 4 Explanation: The longest consecutive elements sequence i…

Given an unsorted array of integers, find the length of the longest consecutive elements sequence.For example,Given [100, 4, 200, 1, 3, 2],The longest consecutive elements sequence is [1, 2, 3, 4]. Return its length: 4.Your algorithm should run in O(…

Given a binary tree, find the length of the longest consecutive sequence path. The path refers to any sequence of nodes from some starting node to any node in the tree along the parent-child connections. The longest consecutive path need to be from p…

Given a binary tree, you need to find the length of Longest Consecutive Path in Binary Tree. Especially, this path can be either increasing or decreasing. For example, [1,2,3,4] and [4,3,2,1] are both considered valid, but the path [1,2,4,3] is not v…

Given a binary tree, find the length of the longest consecutive sequence path. The path refers to any sequence of nodes from some starting node to any node in the tree along the parent-child connections. The longest consecutive path need to be from p…

Given an unsorted array of integers, find the length of the longest consecutive elements sequence. For example, Given [100, 4, 200, 1, 3, 2], The longest consecutive elements sequence is [1, 2, 3, 4]. Return its length: 4. Your algorithm should run i…

Given a binary tree, you need to find the length of Longest Consecutive Path in Binary Tree. Especially, this path can be either increasing or decreasing. For example, [1,2,3,4] and [4,3,2,1] are both considered valid, but the path [1,2,4,3] is not v…

给定一个未排序的整数数组,找出最长连续序列的长度.例如,给出 [100, 4, 200, 1, 3, 2],这个最长的连续序列是 [1, 2, 3, 4].返回所求长度: 4.要求你的算法复杂度为 O(n).详见:https://leetcode.com/problems/longest-consecutive-sequence/description/ Java实现: 方法一: class Solution { public int longestConsecutive(int[] nums)…

题目描述: Longest Consecutive Sequence(最长连续序列) 中文: 给定一个未排序的整数数组,找出最长连续序列的长度. 要求算法的时间复杂度为 O(n). 英文: Given an unsorted array of integers, find the length of the longest consecutive elements sequence. Your algorithm should run in O(n) complexity. class Solu…

题目链接:https://leetcode-cn.com/problems/longest-consecutive-sequence/ 题目大意: 略. 分析: 注意有重复值,序列为空等情况. 代码如下: class Solution { public: int longestConsecutive(vector<int>& nums) { unordered_map< int, int > m1; // 存以 key 为首的最长连续序列的长度 unordered_map&…

最长连续序列 给定一个未排序的整数数组,找出最长连续序列的长度. 说明 要求你的算法复杂度为O(n) 样例 给出数组[100, 4, 200, 1, 3, 2],这个最长的连续序列是 [1, 2, 3, 4],返回所求长度 4 解题 排序后比较简单,快排O(nlogn) 后面只需要O(n)的时间复杂度求解了 发现原数组里面有重复数字的时候,下面方法行不通了. public class Solution { /** * @param nums: A list of integers * @retu…

Given an unsorted array of integers, find the length of the longest consecutive elements sequence. Your algorithm should run in O(n) complexity. Example: Input: [100, 4, 200, 1, 3, 2] Output: 4 Explanation: The longest consecutive elements sequence i…

Given a binary tree, find the length of the longest consecutive sequence path. The path refers to any sequence of nodes from some starting node to any node in the tree along the parent-child connections. The longest consecutive path need to be from p…

Given a k-ary tree, find the length of the longest consecutive sequence path. The path could be start and end at any node in the tree ExampleAn example of test data: k-ary tree 5<6<7<>,5<>,8<>>,4<3<>,5<>,3<>…

给定一个未排序的整数数组,找出最长连续序列的长度. 要求算法的时间复杂度为 O(n). 示例: 输入: [100, 4, 200, 1, 3, 2] 输出: 4 解释: 最长连续序列是 [1, 2, 3, 4].它的长度为 4. 如果不要求算法的时间复杂度为 O(n),排序后遍历即可.沒想出怎么解,看了思路后AC如下,主要是用到Hash映射 public class LongestConsecutiveSequence { public int longestConsecutive(int[]…

124-最长连续序列 给定一个未排序的整数数组,找出最长连续序列的长度. 说明 要求你的算法复杂度为O(n) 样例 给出数组[100, 4, 200, 1, 3, 2],这个最长的连续序列是 [1, 2, 3, 4],返回所求长度 4 标签 数组 思路 由于限定了时间复杂度为 O(n),所以采取先排序再遍历的方式是不适合的,于是以空间换时间,用 set 存储 num 中的数字,方便检测 num 中某个数字是否存在,思路如下: 遍历 num 数组中的每个数字,如果其在 set 中存在,那么将其移除…

转载请注明来自souldak,微博:@evagle 题目(来自leetcode): 给你一个n个数的乱序序列,O(N)找出其中最长的连续序列的长度. 例如给你[100, 4, 200, 1, 3, 2],那么最长的连续序列为[1, 2, 3, 4],所以返回4. 思路: 最简单直接的想法是:将数组排序,然后扫一遍排好序的序列,从中找出最长的即可,这样的话时间是O(nlogn)+O(n),显然不符合题目要求,会超时. 那怎么样不排序就能做出来呢? 我们先抛开算法,想想自己会怎么找,当数组很小,你可…

1. 题目 给定一个未经排序的整数数组,找到最长且连续的的递增序列. 示例 1: 输入: [1,3,5,4,7] 输出: 3 解释: 最长连续递增序列是 [1,3,5], 长度为3. 尽管 [1,3,5,7] 也是升序的子序列, 但它不是连续的,因为5和7在原数组里被4隔开. 示例 2: 输入: [2,2,2,2,2] 输出: 1 解释: 最长连续递增序列是 [2], 长度为1. 注意:数组长度不会超过10000. 来源:力扣(LeetCode) 链接:https://leetcode-cn.c…

674. 最长连续递增序列 674. Longest Continuous Increasing Subsequence 题目描述 给定一个未经排序的整型数组,找到最长且连续的递增序列. Given an unsorted array of integers, find the length of longest continuous increasing subsequence (subarray). 每日一算法2019/5/21Day 18LeetCode674. Longest Conti…

Given an unsorted array of integers, find the length of the longest consecutive elements sequence. For example,Given[100, 4, 200, 1, 3, 2],The longest consecutive elements sequence is[1, 2, 3, 4]. Return its length:4. Your algorithm should run in O(n…