Enlarge Picture (with.Java)

This is the “Enlarge Picture” problem.

We’re going to learn by solving coding test problems, reflecting on the problems we solved, and exploring other ways to solve them.

Let’s start with the problem.

Problem

You have a rectangular-shaped picture file, which is made up of 1 × 1 square-sized pixels.

Given a string array picture representing this picture file and an integer k as parameters, write a solution function that returns a string array that represents the picture file stretched k times horizontally and vertically.

Example input and output

My solution to the ### problem

class Solution {
    public String[] solution(String[] picture, int k) {
        int rows = picture.length;
        int cols = picture[0].length();

        String[] answer = new String[rows * k];

        StringBuilder tempStr = new StringBuilder();
        int count = 0;

        for (String str : picture) {
            for (int i = 0; i < str.length(); i++) {
                char ch = str.charAt(i);
                for (int j = 0; j < k; j++) {
                    tempStr.append(ch);
                }
            }

            for (int j = 0; j < k; j++) {
                answer[count++] = tempStr.toString();
            }

        } tempStr.setLength(0);
    }

} return answer;

solution description

int rows = picture.length; and int cols = picture[0].length();: Count the number of rows and columns in the given picture array.

String[] answer = new String[rows * k];: Create a new string array answer to store the result. The size of the array will be rows * k.

StringBuilder tempStr = new StringBuilder();: Create a StringBuilder object tempStr to store the temporary string.

int count = 0;: Initialize the variable count to keep track of the index of the result array answer.

for (String str : picture) : Iterates over each string str in the given array of pictures.

for (int i = 0; i < str.length(); i++) : Iterating over each character of the string str:

Get the character ch. Repeat that character ch k times and add it to tempStr. for (int j = 0; j < k; j++) : Repeat the string tempStr k times and add it to the answer array.

tempStr.setLength(0);: Empty the temporary string tempStr.

return answer;: Returns the newly created string array answer.