here are the basic Data structures and algorithms questions

**ARRAYS **

- How do you find the missing number in a given integer array of 1 to 100?
- How do you find the duplicate number on a given integer array?
- How do you find the largest and smallest number in an unsorted integer array?
- How do you find all pairs of an integer array whose sum is equal to a given number?
- How do you find duplicate numbers in an array if it contains multiple duplicates?
- How are duplicates removed from a given array in Java?

**LINKED LIST**

- How do you find the middle element of a singly linked list in one pass?
- How do you check if a given linked list contains a cycle?
- How do you find the starting node of the cycle?
- How do you reverse a linked list?
- How do you reverse a singly linked list without recursion?
- How are duplicate nodes removed in an unsorted linked list?
- How do you find the length of a singly linked list?

**STRINGS **

- How do you print duplicate characters from a string?
- How do you check if two strings are anagrams of each other?
- How do you print the first non-repeated character from a string?
- How can a given string be reversed using recursion?
- How do you check if a string contains only digits?
- How are duplicate characters found in a string?

**BINARY TREE**

- How is a binary search tree implemented?
- How do you perform preorder traversal in a given binary tree?
- How do you traverse a given binary tree in preorder without recursion?
- How do you perform an in-order traversal in a given binary tree?
- How do you print all nodes of a given binary tree using inorder traversal without recursion?
- How do you implement a postorder traversal algorithm?

**MISCELLANEOUS**

- How is a bubble sort algorithm implemented?
- How is an iterative quicksort algorithm implemented?
- How do you implement an insertion sort algorithm?
- How is a merge sort algorithm implemented?
- How do you implement a bucket sort algorithm?
- How do you implement a counting sort algorithm?