1. Basic Partial Fill
Background
A developer has an array [1, 2, 3, 4, 5] and needs to replace elements from index 1 to 3 with '*'.
Problem
Manually editing the array is time-consuming and error-prone.
How to use
Input the array, set value to '*', start index to 1, end index to 4.
Outcome
The array becomes [1, '*', '*', '*', 5].