# Max Number of K-Sum Pairs

Category

Two Pointers

Checkbox

Checkbox

Difficulty

Medium

Index

13

Key Ideas

The key idea to solve this problem is to use a hash table to store the frequency of each number and iterate through the array to find pairs that sum up to the target value.

Problem Number

1679

Problem Summary

**Problem Summary:**The problem "Max Number of K-Sum Pairs" is from the LeetCode-75 curated list. Given an array of integers and a target sum, the task is to find the maximum number of pairs that can be formed with the elements in the array, such that their sum is equal to the target.

**Key Pitfalls:**Some key pitfalls to watch out for in this problem include: - Taking into account the frequency of elements in the array while counting pairs. - Handling cases where the same element is used multiple times to form different pairs. - Considering edge cases such as an empty array or a target sum of zero.

Solution Summary

The best solution to solve the Max Number of K-Sum Pairs problem is to use a hash table to keep track of the frequency of each number in the given array.
First, initialize a count variable to 0. Then, iterate through the array and for each number, calculate the complement by subtracting it from the target sum K. Check if the complement exists in the hash table. If it does, increment the count by the frequency of the complement and decrement the frequency of the complement in the hash table.
Finally, return the count, which represents the maximum number of K-sum pairs in the array.
This solution has a time complexity of O(n), where n is the size of the array, as we iterate through the array only once. It also has a space complexity of O(n) to store the hash table.

Tags

Array

Hash Table

Two Pointers