Hackerrank - Lisa's Workbook

Hackerrank – Problem Statement

A description of the problem can be found on Hackerrank.

Solution

Take all problems for each chapter. Fill the pages according to rules – each page contains only k problems, or less if chapter ends. Start counting chapter problems from 1. Check if page contains problem with same number.

I created solution in:

Scala
Java
JavaScript
Ruby

All solutions are also available on my GitHub.

Java

import java.util.*;

public class LisasWorkbook {

    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        int n = stdin.nextInt();
        int k = stdin.nextInt();
        int page = 1;
        int specialProblems = 0;
        for(int i = 0; i < n; i++) {
            int problemsPerChapter = stdin.nextInt();
            for(int p = 1; p <= problemsPerChapter; p++) {
                if(p == page) {
                    specialProblems++;
                }
                if((p != problemsPerChapter) && (p % k == 0)) {
                    page++;
                }
            }
            page++;
        }
        System.out.println(specialProblems);
        stdin.close();
    }
}

import java.util.*;

public class LisasWorkbook {

public static void main(String[] args) {

Scanner stdin = new Scanner(System.in);

int n = stdin.nextInt();

int k = stdin.nextInt();

int page = 1;

int specialProblems = 0;

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

int problemsPerChapter = stdin.nextInt();

for(int p = 1; p <= problemsPerChapter; p++) {

if(p == page) {

specialProblems++;

}

if((p != problemsPerChapter) && (p % k == 0)) {

page++;

}

page++;

}

System.out.println(specialProblems);

stdin.close();

}

JavaScript

'use strict';

const processData = input => {
    const lines = input.split('\n');
    const arr = lines[0].split(/\s+/).map(i => parseInt(i));
    const n = arr[0];
    const k = arr[1];
    const problemsPerChapter = lines[1].split(/\s+/).map(i => parseInt(i));
    let specialProblems = 0;
    let page = 1;
    for(let i = 0; i < n; i++) {
        const problems = problemsPerChapter[i];
        for(let p = 1; p <= problems; p++) {
            if(p === page) {
                specialProblems++;
            }
            if(p !== problems && p % k === 0) {
                page++;
            }
        }
        page++;
    }
    console.log(specialProblems);
};

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

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

'use strict';

const processData = input => {

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

const arr = lines[0].split(/\s+/).map(i => parseInt(i));

const n = arr[0];

const k = arr[1];

const problemsPerChapter = lines[1].split(/\s+/).map(i => parseInt(i));

let specialProblems = 0;

let page = 1;

for(let i = 0; i < n; i++) {

const problems = problemsPerChapter[i];

for(let p = 1; p <= problems; p++) {

if(p === page) {

specialProblems++;

}

if(p !== problems && p % k === 0) {

page++;

}

page++;

}

console.log(specialProblems);

};

process.stdin.resume();

process.stdin.setEncoding("ascii");

var _input = "";

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

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

Scala

import scala.io.Source

object LisasWorkbook extends App {
  val lines = Source.stdin.getLines().toList
  val line1 = lines.head
  val line2 = lines.tail.head

  val arr = line1.split(" ").map(_.toInt)
  val chapters = arr(0)
  val problemsPerPage = arr(1)
  val chapterProblems = line2.split(" ").map(_.toInt)

  val pages = chapterProblems.flatMap(problems => (1 to problems).grouped(problemsPerPage).map(_.toList)).toList
  val specialProblems = (1 to pages.length).count(pageNum => isPageWithSpecialProblem(pages(pageNum - 1), pageNum))
  println(specialProblems)

  def isPageWithSpecialProblem(page: List[Int], pageNum: Int): Boolean = {
    page.contains(pageNum)
  }
}

import scala.io.Source

object LisasWorkbook extends App {

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

val line1 = lines.head

val line2 = lines.tail.head

val arr = line1.split(" ").map(_.toInt)

val chapters = arr(0)

val problemsPerPage = arr(1)

val chapterProblems = line2.split(" ").map(_.toInt)

val pages = chapterProblems.flatMap(problems => (1 to problems).grouped(problemsPerPage).map(_.toList)).toList

val specialProblems = (1 to pages.length).count(pageNum => isPageWithSpecialProblem(pages(pageNum - 1), pageNum))

println(specialProblems)

def isPageWithSpecialProblem(page: List[Int], pageNum: Int): Boolean = {

page.contains(pageNum)

}

Ruby

(n, k) = gets.split.map {|i| i.to_i}
problems_per_chapter = gets.split.map {|i| i.to_i}
page = 1
special_problems = 0
n.times do |i|
  problems = problems_per_chapter[i]
  for p in 1..problems
    special_problems += 1 if p == page
    page += 1 if p != problems && p % k == 0
  end
  page += 1
end

puts special_problems

(n, k) = gets.split.map {|i| i.to_i}

problems_per_chapter = gets.split.map {|i| i.to_i}

page = 1

special_problems = 0

n.times do |i|

problems = problems_per_chapter[i]

for p in 1..problems

special_problems += 1 if p == page

page += 1 if p != problems && p % k == 0

end

page += 1

end

puts special_problems

Pavol Pidanič

I can count to 1023 with 10 fingers

Hackerrank – Lisa’s Workbook

Hackerrank – Problem Statement

Solution

Java

JavaScript

Scala

Ruby

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