Hackerrank - Save the Prisoner

Hackerrank – Problem Statement

A description of the problem can be found on Hackerrank.

Solution

(((sweets % prisoners) + startId) % prisoners) - 1

Modulo finds the id of prisoner who gets the last poisoned candy after all circles distribution. Since the starting id S is not from first prisoner we make an offset. Do modulo again because there are cases when sum of last prisoner and the offset is greater then count of all prisoners.

I created solution in:

Scala
Java
JavaScript
Ruby

All solutions are also available on my GitHub.

Java

import java.util.*;

public class SaveThePrisoner {

    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        int tests = Integer.parseInt(stdin.nextLine());
        for(int i = 0; i < tests; i++) {
            System.out.println(savedPrisoner(stdin.nextLine()));
        }
        stdin.close();
    }

    private static long savedPrisoner(String line) {
        String[] numbers = line.split(" ");
        long prisoners = Long.valueOf(numbers[0]);
        long sweets = Long.valueOf(numbers[1]);
        long startId = Long.valueOf(numbers[2]);

        long saved = (((sweets % prisoners) + startId) % prisoners) - 1;
        if (saved == 0) {
            return prisoners;
        } else {
            return saved;
        }
    }
}

import java.util.*;

public class SaveThePrisoner {

public static void main(String[] args) {

Scanner stdin = new Scanner(System.in);

int tests = Integer.parseInt(stdin.nextLine());

for(int i = 0; i < tests; i++) {

System.out.println(savedPrisoner(stdin.nextLine()));

}

stdin.close();

}

private static long savedPrisoner(String line) {

String[] numbers = line.split(" ");

long prisoners = Long.valueOf(numbers[0]);

long sweets = Long.valueOf(numbers[1]);

long startId = Long.valueOf(numbers[2]);

long saved = (((sweets % prisoners) + startId) % prisoners) - 1;

if (saved == 0) {

return prisoners;

} else {

return saved;

}

JavaScript

'use strict';

const processData = input => {
    const lines = input.split('\n');
    for(let i = 1; i < lines.length; i++) {
        console.log(savedPrisoner(lines[i]));
    }
};

const savedPrisoner = (line) => {
    const numbers = line.split(" ").map(i => parseInt(i));
    const prisoners = numbers[0];
    const sweets = numbers[1];
    const startId = numbers[2];

    const saved = (((sweets % prisoners) + startId) % prisoners) - 1;
    if (saved == 0) {
        return prisoners;
    } else {
        return saved;
    }
};

process.stdin.resume();
process.stdin.setEncoding("ascii");

let _input = "";
process.stdin.on("data", input => _input += input);
process.stdin.on("end", () => processData(_input));

'use strict';

const processData = input => {

const lines = input.split('\n');

for(let i = 1; i < lines.length; i++) {

console.log(savedPrisoner(lines[i]));

}

};

const savedPrisoner = (line) => {

const numbers = line.split(" ").map(i => parseInt(i));

const prisoners = numbers[0];

const sweets = numbers[1];

const startId = numbers[2];

const saved = (((sweets % prisoners) + startId) % prisoners) - 1;

if (saved == 0) {

return prisoners;

} else {

return saved;

}

};

process.stdin.resume();

process.stdin.setEncoding("ascii");

let _input = "";

process.stdin.on("data", input => _input += input);

process.stdin.on("end", () => processData(_input));

Scala

object SaveThePrisoner extends App {
  val lines = Source.stdin.getLines().toList
  val statements = lines.tail
  val savedPrisoners = statements.map(savedPrisoner)

  println(savedPrisoners.mkString("\n"))

  def savedPrisoner(line: String): Long = {
    val numbers = line.split(" ").map(_.toLong)
    val prisoners = numbers(0)
    val sweets = numbers(1)
    val startId = numbers(2)

    val saved = (((sweets % prisoners) + startId) % prisoners) - 1
    if (saved == 0) prisoners else saved
  }
}

object SaveThePrisoner extends App {

val lines = Source.stdin.getLines().toList

val statements = lines.tail

val savedPrisoners = statements.map(savedPrisoner)

println(savedPrisoners.mkString("\n"))

def savedPrisoner(line: String): Long = {

val numbers = line.split(" ").map(_.toLong)

val prisoners = numbers(0)

val sweets = numbers(1)

val startId = numbers(2)

val saved = (((sweets % prisoners) + startId) % prisoners) - 1

if (saved == 0) prisoners else saved

}

Ruby

def saved_prisoner(line)
  numbers = line.split(" ").map {|i| i.to_i}
  prisoners = numbers[0]
  sweets = numbers[1]
  startId = numbers[2]

  saved = (((sweets % prisoners) + startId) % prisoners) - 1;
  return prisoners if (saved == 0)
  saved
end

n = gets.to_i
n.times do
  puts saved_prisoner(gets)
end

def saved_prisoner(line)

numbers = line.split(" ").map {|i| i.to_i}

prisoners = numbers[0]

sweets = numbers[1]

startId = numbers[2]

saved = (((sweets % prisoners) + startId) % prisoners) - 1;

return prisoners if (saved == 0)

saved

end

n = gets.to_i

n.times do

puts saved_prisoner(gets)

end

Pavol Pidanič

I can count to 1023 with 10 fingers

Hackerrank – Save the Prisoner