Porter Interview Questions and Answers

The player who picks the last coin loses the game.

• The game starts with n coins.

• Each player can pick 1 to 5 coins in one turn.

• The player who picks the last coin loses the game.

• Determine if the given n coins will result in a win or loss for the starting player.

Reverse a linked list using recursion, handling all corner cases

• Create a recursive function that takes the head of the linked list as input

• Base case: if the head is null or the list contains only one node, return the head

• Recursively call the function with the next node as input and set its next pointer to the current node

• Set the current node's next pointer to null and return the new head

Write a function to check whether a binary tree is a sub-tree of another binary tree (Check for all corner cases)

• Create a function that traverses both trees and compares them

• Check if the root of the second tree matches any node in the first tree

• Handle cases where one or both trees are empty

• Handle cases where the trees have different structures

Function to add two numbers represented by linked lists and return the sum list.

• Traverse both linked lists and add corresponding nodes, keeping track of carry

• Create a new linked list to store the sum

• Handle cases where linked lists are of different lengths

• Handle cases where the sum has an extra digit due to carry

• Return the sum linked list

Count the number of 0's in a sorted array of 0's and 1's.

• Iterative solution: Traverse the array and count the number of 0's.

• Recursive solution: Divide the array into two halves and recursively count the number of 0's in each half.

• Binary search can also be used to find the first occurrence of 0 and then count the number of 0's after that index.

Program to form a string with first character of all words in a given string.

• Split the string into an array of words

• Iterate through the array and extract the first character of each word

• Join the extracted characters to form the final string

Given a number n, find the number just greater than n using same digits as that of n

• Convert the number to a string and sort the digits in ascending order

• Starting from the rightmost digit, find the first digit that is smaller than the digit to its right

• Swap this digit with the smallest digit to its right that is greater than it

• Sort the digits to the right of the swapped digit in ascending order

• Concatenate the digits to get the next greater number

To build a chess game, you need to create a board, implement the rules of chess, and allow players to make moves.

• Create an 8x8 grid to represent the chess board

• Assign pieces to their starting positions on the board

• Implement the rules of movement for each type of chess piece (e.g. pawn, rook, bishop)

• Allow players to make legal moves and update the board accordingly

• Check for checkmate and end the game when one player's king is in checkmate