Sum of Two Numbers - Online Version

Implement a data structure with the following methods:

• add(int val) adds the value val to the data structure
• find(int val) returns whether there are two elements whose sum equals to val

Constraints

• n ≤ 10,000 where n is the number of times add will be called
• m ≤ 1,000 where m is the number of times find will be called

https://binarysearch.com/problems/Sum-of-Two-Numbers-Online-Version

Examples

Example 1

Input

• methods = ['constructor', 'add', 'find', 'add', 'find']
• arguments = [[], [5], [10], [6], [11]]

Output

• answer = [None, None, False, None, True]

Explanation

• We create a TwoSum first
• Then we add the number 5 to the data structure
• We check if there’s two numbers whose sum is 10. There isn’t, so we return false
• Then we add the number 6 to the data structure
• We check if there’s two numbers whose sum is 11, which there is since 5 + 6 = 11.

Solution