PROBLEM OF THE DAY : 15/06/2024 | Mobile numeric keypad

Welcome to the daily solving of our PROBLEM OF THE DAY with Siddharth Hazra. We will discuss the entire problem step-by-step and work towards developing an optimized solution. This will not only help you brush up on your concepts of Dynamic Programming but also build up problem-solving skills.

There is a standard numeric keypad on a mobile phone. You can only press the current button or buttons that are directly up, left, right, or down from it (for ex if you press 5, then pressing 2, 4, 6 & 8 are allowed). Diagonal movements and pressing the bottom row corner buttons (* and #) are prohibited.

Given a number n, find the number of possible unique sequences of length n that you can create by pressing buttons. You can start from any digit.

Examples

Input: n = 1
Output: 10
Explanation: Number of possible numbers are 10 (0, 1, 2, 3, 4, 5, 6, 7, 8, 9)  

Give the problem a try before going through the video. All the best!!!
Problem Link: https://practice.geeksforgeeks.org/problems/mobile-numeric-keypad5456/1