## 136. Single Number

Given an array of integers, every element appears twice except for one. Find that single one.

Solution:

## 442. Find All Duplicates in an Array

Description:

https://leetcode.com/problems/find-all-duplicates-in-an-array/description/

Code:

Time & Space:
O(n) & O(1)

## 448. Find All Numbers Disappeared in an Array

Description:

https://leetcode.com/problems/find-all-numbers-disappeared-in-an-array/description/

Code:

Code for fastest algorithm:

Time & Space:
O(n) & O(1)

## 495. Teemo Attacking

Description:

https://leetcode.com/problems/teemo-attacking/description/

Code:

Time & Space:
O(n) & O(1)

## 485. Max Consecutive Ones

Description:

https://leetcode.com/problems/max-consecutive-ones/description/

Code:

Time & Space:
O(n) & O(1)

## 628. Maximum Product of Three Numbers

Description:

https://leetcode.com/problems/maximum-product-of-three-numbers/description/

Code:

Time & Space:

O(n) & O(1)

Description:

Code:

Time & Space:
Record: O(1)
Sort: O(nlogn)
Calculate idle: O(1)

Space: O(1)

## 611. Valid Triangle Number

Description:

https://leetcode.com/problems/valid-triangle-number/description/

Algorithm1:

Use for loop for three times.

It works but slow (beats 23.60%)

Code1:

Timing & Space:

O(n^3) & O(1)

Algorithm2:

Code2:

Timing & Space:

Time:

Worst: O(n^2)

Best: O(1)

Space: O(1)