## Find two odd occurring element in an array without using any extra space

Given an array of integers, duplicates appear in it even number of times except two elements which appears odd number of times. Find both odd appearing element without using any extra memory.

## Find pairs with given difference k in the array

Given an unsorted array of integers, print all pairs with given difference k in it.

## Find odd occurring element in an array in single traversal

Given an array of integers, duplicates are present in it in such a way that all duplicates appear even number of times except one which appears odd number of times. Find that odd appearing element in linear time and without using any extra memory.

## 4 sum problem | Quadruplets with given sum

Given an unsorted array of integers, check if it contains four elements tuple (Quadruplets) having given sum.

## Remove duplicates from a linked list in single traversal

Given an unsorted linked list, write a function which deletes any duplicate nodes from the list by traversing the list only once.

## Use struct as key to std::unordered_map in C++

In this post, we will discuss how to use struct as key to std::unordered_map in C++.

## How to use std::pair as key to std::unordered_map in C++

In this post, we will discuss how to use std::pair as key to std::unordered_map in C++.

## Use custom objects as keys to std::map in C++

In this post, we will see how to use custom objects as keys to std::map in C++.

## 3 ways to use std::pair as a key to std::map in C++

In this post, we will see how to use std::pair as a key to std::map in C++. The std::pair in C++ binds together a pair of values of same or different types which can be then accessed through its first and second public members.

## How to use pair as a key in std::unordered_set in C++

In this post, we will discuss how to use std::pair as a key in std::unordered_set in C++.

## How to use an object as a key in std::set in C++

In this post, we will see how to use an object as a key in a std::set in C++.

## How to use std::pair as a key in std::set in C++

In this post, we will see how to use std::pair as a key in a std::set in C++ with and without the comparison object.