Encryption - HackerRank Solution

An English text needs to be encrypted using the following encryption scheme.

First, the spaces are removed from the text. Let L be the length of this text.

Then, characters are written into a grid, whose rows and columns have the following constraints:

⌊√L⌋ <= row <= column <= ⌈√L⌉, where ⌊x⌋ is floor function and ⌈x⌉ is ceil function.

For example, the sentence 

s= if man was meant to stay on the ground god would have given us roots

, after removing spaces is 54 characters long. √54 is between 7 and 8, so it is written in the form of a grid with 7 rows and 8 columns.

ifmanwas  

meanttos          

tayonthe  

groundgo  

dwouldha  

vegivenu  

sroots

Ensure that rows × columns ≥ L

If multiple grids satisfy the above conditions, choose the one with the minimum area, i.e. rows × columns.

The encoded message is obtained by displaying the characters in a column, inserting a space, and then displaying the next column and inserting a space, and so on. For example, the encoded message for the above rectangle is:

imtgdvs fearwer mayoogo anouuio ntnnlvt wttddes aohghn sseoau

You will be given a message to encode and print.

Function Description

Complete the encryption function in the editor below. It should return a single string composed as described.

encryption has the following parameter(s):

• s: a string to encrypt

Input Format

One line of text, the string s

Constraints

1≤|s|≤81

s is comprised only of characters in the range ascii[a-z].

Output Format

Print the encoded message on one line as described.

Sample Input

haveaniceday

Sample Output 0

hae and via ecy

Explanation 0

L=12, √12 is between 3 and 4.

Rewritten with 3 rows and 4 columns:

have

anic

eday

Sample Input 1

feedthedog    

Sample Output 1

fto ehg ee dd

Explanation 1

L=10, √10 is between 3 and 4.

Rewritten with 3 rows and 4 columns:

feed

thed

og

Sample Input 2

chillout

Sample Output 2

clu hlt io

Explanation 2

L=8, √8  is between 2 and 3.

Rewritten with 3 columns and 3 rows (2*3 =6 < 8 so we have to use 3×3.)

chi

llo

ut

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Encryption - HackerRank Solution

import java.io.*;
import java.util.*;
public class Encryption {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        String input = in.nextLine().replaceAll(" ", "");
        int L = input.length();
        int lowerL = (int) Math.floor(Math.sqrt(L));
        int upperL = (int) Math.ceil(Math.sqrt(L));
        int minArea = Integer.MAX_VALUE;
        int x = 0, y = 0;
        for (int i = lowerL; i <= upperL; i++) {
            for (int j = lowerL; j <= upperL; j++) {
                if (i * j >= L) {
                    if (minArea >= i * j) {
                        x = Math.min(i, j);
                        y = Math.max(i, j);
                    }
                    minArea = Math.min(minArea, i * j);
                }
            }
        }
        char[][] grid = new char[x][y];
        int charIndex = 0;
        for (int i = 0; i < grid.length; i++) {
            for (int j = 0; j < grid[i].length; j++) {
                if (charIndex < input.length()) {
                    grid[i][j] = input.charAt(charIndex++);
                } else {
                    grid[i][j] = ' ';
                }
            }
        }
        for (int j = 0; j < grid[0].length; j++) {
            for (int i = 0; i < grid.length; i++) {
                if (grid[i][j] != ' ') {
                    System.out.print(grid[i][j]);
                }
            }
            System.out.print(" ");
        }
        in.close();
    }
}