HackerRank Number Line Jumps Problem Solution

In this post, We are going to solve HackerRank Number Line Jumps Problem.

You are choreographing a circus show with various animals. For one act, you are given two kangaroos on a number line ready to jump in the positive direction (i.e, toward positive infinity).

The first kangaroo starts at location x1 and moves at a rate of v1 meters per jump.
The second kangaroo starts at location x1 and moves at a rate of v1 meters per jump.

You have to figure out a way to get both kangaroos at the same location at the same time as part of the show. If it is possible, return YES, otherwise return NO.

Example

x1 = 2

v1 = 1

x2 = 1

v2 = 2

Function Description

Complete the function kangaroo in the editor below.

kangaroo has the following parameter(s):

int x1, int v1: starting position and jump distance for kangaroo 1
int x2, int v2: starting position and jump distance for kangaroo 2

Returns

string: either YES or NO

Input Format

A single line of four space-separated integers denoting the respective values of x1, v1, x2, and v2.

Sample Input 0

0 3 4 2

Sample Output 0

YES

Explanation 0

The two kangaroos jump through the following sequence of locations:

From the image, it is clear that the kangaroos meet at the same location (number on the number line) after the same number of jumps ( jumps), and we print YES.

Sample Input 1

0 2 5 3

Sample Output 1

NO

Explanation 1

The second kangaroo has a starting location that is ahead (further to the right) of the first kangaroo’s starting location (i.e. x2 > x1, ). Because the second kangaroo moves at a faster rate (meaning v2 > v1) and is already ahead of the first kangaroo, the first kangaroo will never be able to catch up. Thus, we print NO.

Table of Contents

Number Line Jumps C Solution

#include <math.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <assert.h>
#include <limits.h>
#include <stdbool.h>

int main(){
    int x1; 
    int v1; 
    int x2; 
    int v2; 
    int ispossible = 0;
    scanf("%d %d %d %d",&x1,&v1,&x2,&v2);
    if ( v1 == v2 ) {
       if ( x1 == x2 ) {
           ispossible = 1;
       }
    } else {
        float it = (float)(x1-x2)/(v2-v1);
        if ( it >= 0 && (int)it == it ) {
           ispossible = 1;
        }
    }
    if ( ispossible == 1 ) {
        printf("YES");
    } else {
        printf("NO");
    }
    return 0;
}

Number Line Jumps C++ Solution

#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;

bool HasSolution(int x1, int x2, int v1, int v2)
{
    if (v1 <= v2) return false;
    
    return (x2-x1)%((v2-v1)) == 0;
    
}

int main() {
    int x1, x2, v1, v2;
    
    cin >> x1 >> v1 >> x2 >> v2;
    
    if (HasSolution(x1,x2,v1,v2))
    {
        cout << "YES" << endl;
    } else
        {
        cout << "NO" << endl;
    }
    
    return 0;
}

Number Line Jumps C Sharp Solution

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
class Solution {

    static void Main(String[] args) {
        string[] tokens_x1 = Console.ReadLine().Split(' ');
        int x1 = Convert.ToInt32(tokens_x1[0]);
        int v1 = Convert.ToInt32(tokens_x1[1]);
        int x2 = Convert.ToInt32(tokens_x1[2]);
        int v2 = Convert.ToInt32(tokens_x1[3]);
        
        int pass = HopsUntilSeparating(x1, v1, x2, v2);
        if(x1 + pass*v1 == x2 + pass*v2)
            Console.WriteLine("YES");
        else
            Console.WriteLine("NO");
    }
    
    static int HopsUntilSeparating(int x1, int v1, int x2, int v2)
    {
        if(x2 > x1 && v2 >= v1)
            return -1;
        else if (x2 < x1 && v2 <= v1)
            return -1;
        else if (x1 == x2)
            return -1;
        else if (v1 == v2)
            return 0;
        else
            return (Math.Abs(x1-x2) / Math.Abs(v1-v2));
    }
}

Number Line Jumps Java Solution

import java.io.*;
import java.math.*;
import java.security.*;
import java.text.*;
import java.util.*;
import java.util.concurrent.*;
import java.util.function.*;
import java.util.regex.*;
import java.util.stream.*;
import static java.util.stream.Collectors.joining;
import static java.util.stream.Collectors.toList;

class Result {

    /*
     * Complete the 'kangaroo' function below.
     *
     * The function is expected to return a STRING.
     * The function accepts following parameters:
     *  1. INTEGER x1
     *  2. INTEGER v1
     *  3. INTEGER x2
     *  4. INTEGER v2
     */

    public static String kangaroo(int x1, int v1, int x2, int v2) {
        int loc1 = x1;
        int loc2 = x2;
        if (v1 <= v2) {
            return "NO";
        }
        while (loc1 < loc2) {
            loc1 += v1;
            loc2 += v2;
        }
        if (loc1 == loc2) {
            return "YES";
        }
        return "NO";

    }

}

public class Solution {
    public static void main(String[] args) throws IOException {
        BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter(System.getenv("OUTPUT_PATH")));

        String[] firstMultipleInput = bufferedReader.readLine().replaceAll("\\s+$", "").split(" ");

        int x1 = Integer.parseInt(firstMultipleInput[0]);

        int v1 = Integer.parseInt(firstMultipleInput[1]);

        int x2 = Integer.parseInt(firstMultipleInput[2]);

        int v2 = Integer.parseInt(firstMultipleInput[3]);

        String result = Result.kangaroo(x1, v1, x2, v2);

        bufferedWriter.write(result);
        bufferedWriter.newLine();

        bufferedReader.close();
        bufferedWriter.close();
    }
}

Number Line Jumps JavaScript Solution

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

var input_stdin = "";
var input_stdin_array = "";
var input_currentline = 0;

process.stdin.on('data', function (data) {
    input_stdin += data;
});

process.stdin.on('end', function () {
    input_stdin_array = input_stdin.split("\n");
    main();    
});

function readLine() {
    return input_stdin_array[input_currentline++];
}

/////////////// ignore above this line ////////////////////

function main() {
    var x1_temp = readLine().split(' ');
    var x1 = parseInt(x1_temp[0]);
    var v1 = parseInt(x1_temp[1]);
    var x2 = parseInt(x1_temp[2]);
    var v2 = parseInt(x1_temp[3]);
    console.log(myFunc(x1,v1,x2,v2));
    function myFunc(x1,v1,x2,v2){
  if(x1 == x2  && v1 == v2){//if speed and distance is equal
    return 'YES';
  }
  else if(x1 == x2 && v1 > v2){//if initial distance is same but car1 speed > car2's
    return 'NO';
  }
  else if(x1 == x2 && v1 < v2){//if initial distance is same but car1 speed < car2's
    return 'NO';
  }
  else if(x1 < x2 && v1 == v2){//if speed is same but car1 is behind car2
    return 'NO';
  }
  else if(x1 > x2 && v1 == v2){//if speed is same but car1 is ahead of car2
    return 'NO';
  }
  else if((x1 < x2 && v1 < v2) || (x2 < x1 && v2 < v1)){//if distance and speed of each car is less than that of other one
    return 'NO';
  }
  else {
    if((x2-x1) % (v2-v1) === 0){
      return 'YES';
    }
    else {
      return 'NO';
    }
  }
}
    
}

Number Line Jumps Python Solution

#!/bin/python3

import sys

x1,v1,x2,v2 = input().strip().split(' ')
x1,v1,x2,v2 = [int(x1),int(v1),int(x2),int(v2)]

if v1 <= v2 or ((x2 - x1) % (v1 - v2) > 0):
    print('NO')
else:
    print('YES')

Other Solutions