Subarray with Given Sum

Function Name: findSubarrayWithSum

Description

Write a function that finds a contiguous subarray within a one-dimensional array of positive integers which adds up to a given sum.

The function should return the indices of the first and last elements in the subarray that adds up to the specified sum, or indicate that no such subarray exists.

The array and sum will be passed as parameters to the function.

If there are multiple such subarrays, the function should return the indices of the subarray with the smallest starting index.

Requirements

• The function must accept two arguments: an array of positive integers and the target sum.
• The function should return a tuple or array with two elements representing the starting and ending indices of the subarray.
• Return a special value (like `null`, `None`, `-1`, etc. depending on the language) if no subarray is found.
• The array will not be empty and will contain only positive integers.
• The target sum will be a positive integer.
• Optimize the function for time complexity.

Examples

If the function is called with `([1, 4, 20, 3, 10, 5], 33)`, it should return `[2, 4]` because the subarray `[20, 3, 10]` adds up to 33.Calling the function with `([1, 2, 3, 7, 5], 12)` should return `[3, 4]` as the subarray `[7, 5]` sums to 12.If the function is passed `([1, 2, 3, 4, 5], 9)` it should return `[2, 4]`, because the subarray `[3, 4, 5]` adds up to 9.If no subarray matches, for example if the function is called with `([1, 2, 3, 4], 10)` it should return `null`.

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