# Yet More Leetcode Contributions

If you’ve been following my recent posts you know that I submitted a question contribution to leetcode.

Determined to have at least one of my contributions accepted, today I submitted three more. They are much simpler than my first and all inspired by my SwiftSyntax Tutorial. I was completely transparent in my reason for submitting them. I’m not doing it because I saw these questions in interviews. I’m doing it just because I can!

## Submission 1 - Rewriting Integer Literals

This one is taken directly from the SwiftSyntax tutorial.

### Question Title

Reformat Integer Literals

### Reason for Submission

I want to contribute this question for points.

### Description

Some programming languages allow you to write integers with underscores to enhance readability. For example, in Swift you can write

let x = 1_000_000


to declare an integer literal. To make integer literals more readable we wish to group the digits into threes, starting from the least significant digit.

Given a string of digits with no underscores in it, return a reformatted string containing the digits separated by underscores in the manner described.

Example:

• Given literal = "123456789", return "123_456_789".

• Given literal = "99999999", return "99_999_999".

### Solutions

This is a straightforward solution! The (Swift) code speaks for itself. Here is the leetcode playground: https://leetcode.com/playground/5Jw8YD8x

### Test Cases

Input: literal = "123456789"

Output: "123_456_789"

Input: literal = "11111111111"

Output: "11_111_111_111"

Input: literal = "69"

Output: "69"

String

ElvisTheKing

## Submission 2 - Convert Snake Case to Camel Case

This one is also taken directly from my SwiftSyntax Tutorial.

### Question Title

Convert Snake Case to Camel Case

### Reason for Submission

I want to contribute this question for the points.

### Description

Snake case and Camel case are two different conventions for variable and parameter names.

Given an identifier written in snake case, convert it to camel case.

Examples

identifier = scary_snake, return scarySnake

identifer = _even__scarier____snake_, return _evenScarierSnake_

Note that leading and trailing underscores are not considered part of the “snake”.

### Solutions

A straightforward Swift solution

https://leetcode.com/playground/jQMCN93x

### Test Cases

Input: scary_snake

Output: scarySnake

Input: _even__scarier____snake_

Output: _evenScarierSnake_

Input: x_123_hello

Output: x123Hello

Input: alreadyCamelCase

Output: alreadyCamelCase

Input: justonelongword

Output: justonelongword

Input: a_b_c_d_e_f_g

Output: aBCDEFG

String

ElvisTheKing

## Submission 3 - Convert Camel Case to Snake Case

This wasn’t in my SwiftSyntax tutorial but was easy enough to come up with. As you can clearly see it’s just the opposite of the previous contribution.

### Question Title

Convert Camel Case to Snake Case

### Reason for Submission

I want to contribute this question for the points.

### Description

Snake case and Camel case are two different conventions for variable and parameter names.

Given an identifier written in camel case, convert it to snake case.

### Solutions

A straightforward Swift solution

https://leetcode.com/playground/Ro6UPf4u

### Test Cases

input: "helloWorld"

output: "hello_world"

input: "ThisIsAString"

output: "this_is_a_string"

input: "test123"

output: "test123"

String

### Contributor

ElvisTheKing

Written on November 23, 2019