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Grokking the Coding Interview Patterns

Encode and Decode Strings

Understand how to create encode and decode methods that convert arrays of strings to a single string and back. This lesson focuses on efficient data transmission and manipulation using bitwise operations, helping you handle encoding challenges common in coding interviews.

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Statement

Create a method, encode, that converts an array of strings into a single string and then sends it over the network. Create another method, decode, that takes the encoded string and converts it back into the original array of strings.

Constraints:

  • 1≤1 \leq strings.length ≤100\leq 100
  • 0≤0 \leq strings[i].length ≤100\leq 100
  • strings[i] consist of any possible combinations of characters from 256 valid ASCII characters.

Examples

Understand the problem

Let’s take a moment to make sure you’ve correctly understood the problem. The quiz below helps you check if you’re solving the correct problem:

Encode and Decode Strings

1.

What will be the input data type of the encode function?

A.

String

B.

Array of strings

C.

Integer

D.

Boolean

1 / 4

Figure it out!

We have a game for you to play. Rearrange the logical building blocks to develop a clearer understanding of how to solve this problem.

Sequence - Vertical
Drag and drop the cards to rearrange them in the correct sequence.
1
2
3
4
5

Try it yourself

Implement your solution in the following coding playground.

Java
usercode > Solution.java
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
public class Solution {
    public static String encode(List<String> strings) {
        // Replace this placeholder return statement with your code
        StringBuilder encodedString = new StringBuilder();
        return encodedString.toString();
    }
    public static List<String> decode(String str) {
        // Replace this placeholder return statement with your code
        List<String> decodedString = new ArrayList<>();
        return decodedString;
    }
}
Encode and Decode Strings