## Find an Element in 2 dimensional sorted array

Objective : Write an algorithm to find an Element in 2 dimensional array where rows and columns are sorted respectively.

Input: A two dimensional sorted array, arrA[][].

Output : True or false based on whether element exists and its location

Approach:

## Find Whether Given String is palindrome or Not.

Objective : Write an algorithm to find Whether Given String is palindrome or Not.

Input:  A String,

Output: true or false on whether string is palindrome or not

Approach:

• Use recursive approach
• Compare first and last characters if they are not same- return false
• If they are same make, remove the first and last characters and make a recursive call.

Example:

```Jain niaJ => compare ‘J’ with ‘J’ =>returns true

ain nia => compare ‘a’ with ‘a’ =>returns true

in ni => compare ‘i’ with ‘i’ =>returns true

n n => compare ‘n’ with ‘n’ =>returns true

string length <2 => returns true```

## Find two Missing Numbers in a Sequence of Consecutive Numbers

Objective : Write an algorithm to find two Missing Numbers in a Sequence of Consecutive Numbers

Input:  Array, arrA[] with two missing numbers and Range

Output : Two missing numbers

Approach:

• Approach is very simple, Add all the given numbers say S
• Calculate sum of N numbers by formula n(n+1)/2 , say N
• Find sum of two missing numbers a+b = N-S

## Find a Missing Number From a Sequence of Consecutive Numbers

Objective : You have been asked to Write an algorithm Find a Missing Number From a Sequence of Consecutive Numbers

Input:  Array, arrA[] with a missing number and Range

Output : missing number

Approach:

• Approach is very simple, Add all the given numbers say S
• Calculate sum of N numbers by formula n(n+1)/2 , say N
• Find missing number m = N-S