SDE - 1

You have been given a square chessboard of size ‘N x N’. The position coordinates of the Knight and the position coordinates of the target are also given.

Your task is to find out the minimum steps a Knight will take to reach the target position.

Example:

knightPosition: {3,4}
targetPosition: {2,1}

The knight can move from position (3,4) to positions (1,3), (2,2) and (4,2). Position (4,2) is selected and the ‘stepCount’ becomes 1. From position (4,2), the knight can directly jump to the position (2,1) which is the target point and ‘stepCount’ becomes 2 which is the final answer. 

Note:

1. The coordinates are 1 indexed. So, the bottom left square is (1,1) and the top right square is (N, N).

2. The knight can make 8 possible moves as given in figure 1.

3. A Knight moves 2 squares in one direction and 1 square in the perpendicular direction (or vice-versa).

You are given a Singly Linked List of integers and a positive integer 'K'. Modify the linked list by reversing every alternate 'K' nodes of the linked list.

A singly linked list is a type of linked list that is unidirectional, that is, it can be traversed in only one direction from head to the last node (tail).

Note:

If the number of nodes in the list or in the last group is less than 'K', just reverse the remaining nodes. 

Example:

Linked list: 5 6 7 8 9 10 11 12
K: 3 

Output: 7 6 5 8 9 10 12 11

We reverse the first 'K' (3) nodes and then skip the next 'K'(3) nodes. Now, since the number of nodes remaining in the list (2) is less than 'K', we just reverse the remaining nodes (11 and 12). 

Note:

You need to reverse the first 'K' nodes and then skip the 'K' nodes and so on. 5 6 7 10 9 8 11 12 is not the correct answer for the given linked list. 

You are given an array ‘arr’ of size ‘N’ and an integer ‘K’. Your task is to find the maximum subset-sum of the array that is not greater than ‘K’.

For Example:

Your are given ‘arr’ = [1, 3, 5, 9], and ‘K’ = 16, we can take the subset of elements [9, 5 ,1] which sums up to 15. Hence the answer is 15.

A thief is robbing a store and can carry a maximal weight of W into his knapsack. There are N items and the ith item weighs wi and is of value vi. Considering the constraints of the maximum weight that a knapsack can carry, you have to find and return the maximum value that a thief can generate by stealing items.

Ninja developed a love for arrays and strings so this time his teacher gave him an array of strings, ‘A’ of size ‘N’. Each element of this array is a string. The teacher taught Ninja about prefixes in the past, so he wants to test his knowledge.

A string is called a complete string if every prefix of this string is also present in the array ‘A’. Ninja is challenged to find the longest complete string in the array ‘A’.If there are multiple strings with the same length, return the lexicographically smallest one and if no string exists, return "None".

Note :

String ‘P’ is lexicographically smaller than string ‘Q’, if : 

1. There exists some index ‘i’ such that for all ‘j’ < ‘i’ , ‘P[j] = Q[j]’ and ‘P[i] < Q[i]’. E.g. “ninja” < “noder”.

2. If ‘P’ is a prefix of string ‘Q’, e.g. “code” < “coder”.

Example :

N = 4
A = [ “ab” , “abc” , “a” , “bp” ] 

Explanation : 

Only prefix of the string “a” is “a” which is present in array ‘A’. So, it is one of the possible strings.

Prefixes of the string “ab” are “a” and “ab” both of which are present in array ‘A’. So, it is one of the possible strings.

Prefixes of the string “bp” are “b” and “bp”. “b” is not present in array ‘A’. So, it cannot be a valid string.

Prefixes of the string “abc” are “a”,“ab” and “abc” all of which are present in array ‘A’. So, it is one of the possible strings.

We need to find the maximum length string, so “abc” is the required string.

Given a number ‘N', the task is to find the total number of derangements of a set of ‘N’ elements.

A ‘Derangement’ is a permutation of 'N' elements, such that no element appears in its original position. For example, a derangement of {0, 1, 2, 3} is {2, 3, 1, 0}.

For example, 'N' = 2 , {0, 1} and {1, 0} are the only derangement therefore output will be 1.

Two players 'X' and 'Y', are playing a coin game. Initially, there are 'N' coins. Each player can pick exactly 'A' coins or 'B' coins or 1 coin. A player loses the game if he is not able to pick any coins. 'X' always starts the game, and each player plays optimally. You are supposed to find which player wins the coin game.