## HackerRank: Repeated String

### Problem

Lilah has a string, s, of lowercase English letters that she repeated infinitely many times.

Given an integer, n, find and print the number of letter a‘s in the first letters of Lilah’s infinite string.

### Input Format

The first line contains a single string, s.
The second line contains an integer, n.

### Constraints

• 1<=|s|<=100
• 1<=|n|<=10^12
• For 25% of the test cases, n <= 10^6

### Output Format

Print a single integer denoting the number of letter a’s in the first letters of the infinite string created by repeating infinitely many times.

aba
10

7

### Explanation 0

The first n = 10 letters of the infinite string are abaabaabaa. Because there are 7 a‘s, we print on a new line.

a
1000000000000

1000000000000

### Explanation 1

Because all of the first n=1000000000000 letters of the infinite string are a, we print 1000000000000 on a new line.

## HackerRank: Circular Array Rotation

### Problem

John Watson performs an operation called a right circular rotation on an array of integers, [a(0),a(1).a(2)...a(n-2),a(n-1)]. After performing one right circular rotation operation, the array is transformed from

[a(0),a(1).a(2)...a(n-2),a(n-1)]

to

[a(n-1),a(0),a(1).a(2)...a(n-2)].

Watson performs this operation k times. To test Sherlock’s ability to identify the current element at a particular position in the rotated array, Watson asks q queries, where each query consists of a single integer, m, for which you must print the element at index in the rotated array (i.e., the value of a(m)).

#### Input Format

The first line contains space-separated integers, n, k, and q, respectively.
The second line contains space-separated integers, where each integer i describes array element a(i)(where 0 <= i <= n).
Each of the q subsequent lines contains a single integer denoting m.

#### Constraints

• 0 <= i <= 10^5
• 0 <= a(i) <= 10^5
• 0 <= k <= 10^5
• 0 <= q <= 500
• 0 <= m <= N-1

#### Output Format

For each query, print the value of the element at index m of the rotated array on a new line.

##### Sample Input
3 2 3
1 2 3
0
1
2

##### Sample Output
2
3
1


#### Explanation

After the first rotation, the array becomes [3,1,2].
After the second (and final) rotation, the array becomes [2,3,1].

Let’s refer to the array’s final state as array b. For each query, we just have to print the value of b(m) on a new line:

• m=0 , so we print 2 on a new line.
• m=1 , so we print 3 on a new line.
• m=2 , so we print 1 on a new line.

## Problem:

Sample Game

Draughts is a two player board game which is played on a 8X8 grid of cells and is played on opposite sides of the game-board. Each player has an allocated color, Red ( First Player ) or White ( Second Player ) being conventional. Players take turns involving diagonal moves of uniform game pieces in the forward direction only and mandatory captures by jumping over opponent pieces.

Rules:

• Player can only move diagonally to the adjacent cell and in forward direction, if the diagonally adjacent cell is vacant.
• A player may not move an opponent’s piece.
• If the diagonally adjacent cell contains an opponent’s piece, and the cell immediately beyond it is vacant, the opponent’s piece may be captured (and removed from the game) by jumping over it in the forward direction only.
• If a player made a jump, then its mandatory to keep on jumping as long as the jump is possible.
• Player cannot move to the diagonally adjacent cell once the player made a jump.

The game will end when any of the players don’t have any move left. At the end of the game the player with majority of pieces will win.

We will play it on an 8X8 grid. The top left of the grid is [0,0] and the bottom right is [7,7].

Input:
The input will be a 8X8 matrix consisting only of 0o2. Then another line will follow which will contain a number –  1 or 2 which is your player id. In the given matrix, top-left is [0,0] and bottom-right is [7,7]. The x-coordinate increases from left to right, and y-coordinate increases from top to bottom.

The cell marked 0 means it doesn’t contain any stones. The cell marked 1 means it contains first player’s stone which is Red in color. The cell marked 2 means it contains second player’s stone which is white in color.

Output:
In the first line print the coordinates of the cell separated by space, the piece he / she wants to move.
In second line print an integer N, number of steps or jumps the piece will make in one move.
In the next N lines print the coordinates of the cells in which the piece will make jump.
You must take care that you don’t print invalid coordinates. For example, [1,1] might be a valid coordinate in the game play if [1,1] in diagonal to the piece in which is going to jump, but [9,10] will never be. Also if you play an invalid move or your code exceeds the time/memory limit while determining the move, you lose the game.

Starting state
The starting state of the game is the state of the board before the game starts.

0 1 0 1 0 1 0 1
1 0 1 0 1 0 1 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 2 0 2 0 2 0 2
2 0 2 0 2 0 2 0


First Input
This is the input give to the first player at the start of the game.

0 1 0 1 0 1 0 1
1 0 1 0 1 0 1 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 2 0 2 0 2 0 2
2 0 2 0 2 0 2 0
1

SAMPLE INPUT
0 1 0 1 0 1 0 1
1 0 1 0 1 0 0 0
0 0 0 0 0 1 0 0
0 0 0 0 2 0 0 0
0 0 0 0 0 0 0 0
0 0 2 0 0 0 0 0
0 0 0 2 0 0 0 2
2 0 2 0 2 0 2 0
1
SAMPLE OUTPUT
2 5
2
4 3
6 1

Explanation

This is player 1’s turn, and the player will move the piece at [2,5] and will make two jumps. First jump will be at [4,3and second jump will be at [6,1]

After his/her move the state of game becomes:

0 1 0 1 0 1 0 1
1 0 1 0 1 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
0 1 0 2 0 2 0 2
2 0 2 0 2 0 2 0


This state will be fed as input to program of player 2.

Other valid move for the first player is

2 5
1
3 6


But the following are invalid moves.
Case 1:

2 5
1
4 3


Because after making a jump its possible to jump again and its mandatory to jump as long as its possible to jump.

Case 2:

2 5
2
4 3
5 4


Because after making a jump its invalid to move to diagonally adjacent cell.

Here is the code of the Random Bot.

Time Limit:1.0 sec(s) for each input file.
Memory Limit:256 MB
Source Limit:1024 KB

## Solution

This is the solution submitted by me

## Problem:

Reversi is a two player board game which is played on a 10 x 10 grid of cells. Each player has an allocated color, Black ( First Player ) or White ( Second Player ) being conventional. Players take turns placing a stone of their color on a single cell. A player must place a stone on the board, in such a position that there exists at least one straight (horizontal, vertical, or diagonal) occupied line between the new stone and another stone of same color, with one or more contiguous other color stone between them.

During a game, any stone of the opponent’s color that are in a straight line and bounded by the stone just placed and another stone of the current player’s color are turned over to the current player’s color. The game will end when the board is completely filled or both the players don’t have any move left. At the end of the game the player with majority of stone will win.

We will play it on an 10 x 10 grid. The top left of the grid is [0,0] and the bottom right is [9,9]. The rule is that a cell[i,j] is connected to any of top, left, right, or bottom cell.

Input:
The input will be a 10 x 10 matrix consisting only of 0,1,2 or 3. Then another line will follow which will contain a number – 1 or 2 which is your player id.

In the given matrix, top-left is [0,0] and bottom-right is [9,9].

In cell[row,column], row increases from top to bottom and column increases from left to right.

The cell marked 0 means it doesn’t contain any stones. The cell marked 1 means it contains first player’s stone which is Black in color. The cell marked 2 means it contains second player’s stone which is white in color. The cell marked 3 means it is a valid place for player whose turn it is.

Output:
Print the coordinates of the cell separated by space, where you want to play your move. You must take care that you don’t print invalid coordinates. For example, [1] might be a valid coordinate in the game play if cell[i,j]=3, but [10] will never be. Also if you play an invalid move or your code exceeds the time/memory limit while determining the move, you lose the game.

Starting state
The starting state of the game is the state of the board before the game starts.

0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 2 1 0 0 0 0
0 0 0 0 1 2 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0


First Input
This is the input give to the first player at the start of the game.

0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 3 0 0 0 0 0
0 0 0 3 2 1 0 0 0 0
0 0 0 0 1 2 3 0 0 0
0 0 0 0 0 3 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
1


Scoring
The scores are calculated by running tournament of all submissions. Your latest submission will be taken into tournament. Scores are assigned according to the Glicko-2 rating system. For more information and questions, see Bot problem judge.

SAMPLE INPUT

0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 3 0 0 0 0 0
0 0 0 3 2 1 3 0 0 0
0 0 0 0 2 2 0 0 0 0
0 0 0 3 1 1 2 3 0 0
0 0 0 1 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
1
SAMPLE OUTPUT
4 3

Explanation

This is player 1’s turn, and the player puts his/her stone in cell[4,3].
After his/her move the state of game becomes:

0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0
0 0 0 3 0 3 0 0 0 0
0 0 0 1 1 1 0 0 0 0
0 0 0 3 1 2 0 0 0 0
0 0 0 3 1 1 2 0 0 0
0 0 0 1 0 3 0 0 0 0
0 0 3 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0


This state will be fed as input to program of player 2.

Time Limit:1.0 sec(s) for each input file.
Memory Limit: 256 MB
Source Limit: 1024 KB
Marking Scheme:Marks are awarded if any testcase passes.
Allowed Languages:C, CPP, CLOJURE, CSHARP, D, ERLANG, FSHARP, GO, GROOVY, HASKELL, JAVA, JAVA8, JAVASCRIPT, JAVASCRIPT_NODE, LISP, LISP_SBCL, LUA, OBJECTIVEC, OCAML, OCTAVE, PASCAL, PERL, PHP, PYTHON, PYTHON3, R, RACKET, RUBY, RUST, SCALA, SWIFT, VB

## HackerRank: Gemstones

### Problem

John has discovered various rocks. Each rock is composed of various elements, and each element is represented by a lower-case Latin letter from ‘a’ to ‘z’. An element can be present multiple times in a rock. An element is called a gem-element if it occurs at least once in each of the rocks.

Given the list of N rocks with their compositions, display the number of gem-elements that exist in those rocks.

Input Format

The first line consists of an integer, N, the number of rocks.
Each of the next N lines contains a rock’s composition. Each composition consists of lower-case letters of English alphabet.

Constraints
1N100
Each composition consists of only lower-case Latin letters (‘a’-‘z’).
1≤ length of each composition 100

Output Format

Print the number of gem-elements that are common in these rocks. If there are none, print 0.

Sample Input

3
abcdde
baccd
eeabg


Sample Output

2


Explanation

Only “a” and “b” are the two kinds of gem-elements, since these are the only characters that occur in every rock’s composition.

## HackerRank: The Love-Letter Mystery

### Problem

James found a love letter his friend Harry has written for his girlfriend. James is a prankster, so he decides to meddle with the letter. He changes all the words in the letter into palindromes.

To do this, he follows two rules:

1. He can reduce the value of a letter, e.g. he can change d to c, but he cannot change c to d.
2. In order to form a palindrome, if he has to repeatedly reduce the value of a letter, he can do it until the letter becomes a. Once a letter has been changed to a, it can no longer be changed.

Each reduction in the value of any letter is counted as a single operation. Find the minimum number of operations required to convert a given string into a palindrome.

Input Format

The first line contains an integer T, i.e., the number of test cases.
The next T lines will contain a string each. The strings do not contain any spaces.

Constraints
1T10
1 length of string 10^4
All characters are lower case English letters.

Output Format

A single line containing the number of minimum operations corresponding to each test case.

Sample Input

4
abc
abcba
abcd
cba


Sample Output

2
0
4
2


Explanation

1. For the first test case, abc -> abb -> aba.
2. For the second test case, abcba is already a palindromic string.
3. For the third test case, abcd -> abcc -> abcb -> abca = abca -> abba.
4. For the fourth test case, cba -> bba -> aba.

## HackerRank: Alternating Characters

### Problem

Shashank likes strings in which consecutive characters are different. For example, he likes ABABA, while he doesn’t like ABAA. Given a string containing characters A and B only, he wants to change it into a string he likes. To do this, he is allowed to delete the characters in the string.

Input Format

The first line contains an integer T, i.e. the number of test cases.
The next T lines contain a string each.

Output Format

For each test case, print the minimum number of deletions required.

Constraints

1T10
1≤ length of string 10^5

Sample Input

5
AAAA
BBBBB
ABABABAB
BABABA
AAABBB


Sample Output

3
4
0
0
4


Explanation

AAAA A, 3 deletions
BBBBB B, 4 deletions
ABABABAB ABABABAB, 0 deletions
BABABA BABABA, 0 deletions
AAABBB AB, 4 deletions because to convert it to AB we need to delete 2 A’s and 2 B’s

## HackerRank: Modified Kaprekar Numbers

### Problem:

A modified Kaprekar number is a positive whole number n with d digits, such that when we split its square into two pieces – a right hand piece r with d digits and a left hand piece l that contains the remaining d or d1 digits, the sum of the pieces is equal to the original number (i.e. l + r = n).

Note: r may have leading zeros.

Here’s an explanation from Wikipedia about the ORIGINAL Kaprekar Number (spot the difference!): In mathematics, a Kaprekar number for a given base is a non-negative integer, the representation of whose square in that base can be split into two parts that add up to the original number again. For instance, 45 is a Kaprekar number, because 45² = 2025 and 20+25 = 45.

You are given the two positive integers p and q, where p is lower than q. Write a program to determine how many Kaprekar numbers are there in the range between p and q (both inclusive) and display them all.

Input Format

There will be two lines of input: p, lowest value q, highest value

Constraints:
0<p<q<100000

Output Format

Output each Kaprekar number in the given range, space-separated on a single line. If no Kaprekar numbers exist in the given range, print INVALID RANGE.

Sample Input

1
100


Sample Output

1 9 45 55 99

Explanation

1, 9, 45, 55, and 99 are the Kaprekar Numbers in the given range.

## HackerRank: Paint The Tiles

Problem

Nikita has a line of N tiles indexed from 0 to N−1. She wants to paint them to match a color configuration, C, which is comprised of 2 colors: Red(R) and Blue(B)

In one stroke, Nikita can paint 1 or more adjacent tiles a single color. After she finishes painting, each tile(i) should be painted color C(i).

It should be noted that it is not allowed to apply more than 1 stroke on a tile.

Given the required color configuration, find and print the minimum number of strokes required for Nikita to paint all N tiles.

Note: In a line of tiles, 2 tiles with the indices i and j are considered adjacent only if |ji|=1.

Input Format

The first line contains a single integer, N, denoting the number of tiles to be painted.
The second line contains a string, C, denoting the desired color configuration.

For each character C(i) in C:

• If C(i)=“R”, it means the ith tile must be painted red.
• If C(i)=“B”, it means the ith tile must be painted blue.

Constraints

• 1N1000
• C(i){“R”, “B”}

Output Format

Print the minimum number of strokes required to paint all tiles in the desired color configuration.

Sample Input 0

5
RRRRR


Sample Output 0

1


Sample Input 1

5
RRBRR


Sample Output 1

3


Sample Input 2

5
BRBRB


Sample Output 2

5


Explanation

Sample Case 0:

Nikita will paint all 5 consecutive tiles red in a single stroke:

Sample Case 1:

Nikita will need 3 strokes to paint all 5 tiles:

Solution:

## HackerRank: The Time in Words

### Problem

Given the time in numerals we may convert it into words, as shown below:

5:00 → five o’ clock
5:01 → one minute past five
5:10 → ten minutes past five
5:30 → half past five
5:40 → twenty minutes to six
5:45 → quarter to six
5:47 → thirteen minutes to six
5:28 → twenty eight minutes past five

Write a program which prints the time in words for the input given in the format mentioned above.

Input Format

There will be two lines of input:
H, representing the hours
M, representing the minutes

Constraints
1H<12
0M<60

Output Format

Display the time in words.

Sample Input

5
47


Sample Output

thirteen minutes to six