first-missing-positive

java

python

python3

mysql

mssql

oraclesql

csharp

javascript

typescript

bash

swift

kotlin

dart

golang

ruby

scala

rust

racket

erlang

elixir

pythondata

postgresql

cangjie

Algorithms

Given an unsorted integer array <code>nums</code>. Return the smallest positive integer that is not present in <code>nums</code>.

You must implement an algorithm that runs in <code>O(n)</code> time and uses <code>O(1)</code> auxiliary space.

&nbsp;
Example 1:

<pre>
Input: nums = [1,2,0]
Output: 3
Explanation: The numbers in the range [1,2] are all in the array.
</pre>

Example 2:

<pre>
Input: nums = [3,4,-1,1]
Output: 2
Explanation: 1 is in the array but 2 is missing.
</pre>

Example 3:

<pre>
Input: nums = [7,8,9,11,12]
Output: 1
Explanation: The smallest positive integer 1 is missing.
</pre>

&nbsp;
Constraints:

<ul>
	<li><code>1 &lt;= nums.length &lt;= 105</code></li>
	<li><code>-231 &lt;= nums[i] &lt;= 231 - 1</code></li>
</ul>

firstMissingPositive

First Missing Positive

Missing Number

missing-number

丢失的数字

Find the Duplicate Number

find-the-duplicate-number

寻找重复数

Find All Numbers Disappeared in an Array

find-all-numbers-disappeared-in-an-array

找到所有数组中消失的数字

Couples Holding Hands

couples-holding-hands

情侣牵手

Smallest Number in Infinite Set

smallest-number-in-infinite-set

无限集中的最小数字

Maximum Number of Integers to Choose From a Range I

maximum-number-of-integers-to-choose-from-a-range-i

从一个范围内选择最多整数 I

Smallest Missing Non-negative Integer After Operations

smallest-missing-non-negative-integer-after-operations

执行操作后的最大 MEX

Maximum Number of Integers to Choose From a Range II

maximum-number-of-integers-to-choose-from-a-range-ii

从一个范围内选择最多整数 II

Smallest Missing Integer Greater Than Sequential Prefix Sum

smallest-missing-integer-greater-than-sequential-prefix-sum

大于等于顺序前缀和的最小缺失整数

Array

Hash Table

给你一个未排序的整数数组 <code>nums</code> ，请你找出其中没有出现的最小的正整数。
请你实现时间复杂度为 <code>O(n)</code> 并且只使用常数级别额外空间的解决方案。

&nbsp;

示例 1：

<pre>
输入：nums = [1,2,0]
输出：3
解释：范围 [1,2] 中的数字都在数组中。</pre>

示例 2：

<pre>
输入：nums = [3,4,-1,1]
输出：2
解释：1 在数组中，但 2 没有。</pre>

示例 3：

<pre>
输入：nums = [7,8,9,11,12]
输出：1
解释：最小的正数 1 没有出现。</pre>

&nbsp;

提示：

<ul>
	<li><code>1 &lt;= nums.length &lt;= 105</code></li>
	<li><code>-231 &lt;= nums[i] &lt;= 231 - 1</code></li>
</ul>