longest-consecutive-sequence

java

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python3

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oraclesql

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cangjie

Algorithms

Given an unsorted array of integers <code>nums</code>, return the length of the longest consecutive elements sequence.

You must write an algorithm that runs in&nbsp;<code>O(n)</code>&nbsp;time.

&nbsp;
Example 1:

<pre>
Input: nums = [100,4,200,1,3,2]
Output: 4
Explanation: The longest consecutive elements sequence is <code>[1, 2, 3, 4]</code>. Therefore its length is 4.
</pre>

Example 2:

<pre>
Input: nums = [0,3,7,2,5,8,4,6,0,1]
Output: 9
</pre>

Example 3:

<pre>
Input: nums = [1,0,1,2]
Output: 3
</pre>

&nbsp;
Constraints:

<ul>
	<li><code>0 &lt;= nums.length &lt;= 105</code></li>
	<li><code>-109 &lt;= nums[i] &lt;= 109</code></li>
</ul>

longestConsecutive

Longest Consecutive Sequence

Binary Tree Longest Consecutive Sequence

binary-tree-longest-consecutive-sequence

二叉树最长连续序列

Find Three Consecutive Integers That Sum to a Given Number

find-three-consecutive-integers-that-sum-to-a-given-number

找到和为给定整数的三个连续整数

Maximum Consecutive Floors Without Special Floors

maximum-consecutive-floors-without-special-floors

不含特殊楼层的最大连续楼层数

Length of the Longest Alphabetical Continuous Substring

length-of-the-longest-alphabetical-continuous-substring

最长的字母序连续子字符串的长度

Find the Maximum Number of Elements in Subset

find-the-maximum-number-of-elements-in-subset

子集中元素的最大数量

Union Find

Array

Hash Table

给定一个未排序的整数数组 <code>nums</code> ，找出数字连续的最长序列（不要求序列元素在原数组中连续）的长度。

请你设计并实现时间复杂度为&nbsp;<code>O(n)</code> 的算法解决此问题。

&nbsp;

示例 1：

<pre>
输入：nums = [100,4,200,1,3,2]
输出：4
解释：最长数字连续序列是 [1, 2, 3, 4]。它的长度为 4。</pre>

示例 2：

<pre>
输入：nums = [0,3,7,2,5,8,4,6,0,1]
输出：9
</pre>

示例 3：

<pre>
输入：nums = [1,0,1,2]
输出：3
</pre>

&nbsp;

提示：

<ul>
	<li><code>0 &lt;= nums.length &lt;= 105</code></li>
	<li><code>-109 &lt;= nums[i] &lt;= 109</code></li>
</ul>