Mowing the Lawn

Create a function that takes in an array of grass heights and a variable sequence of lawn mower cuts and outputs the array of successive grass heights.

If after a cut, any single element in the array reaches zero or negative, return "Done" instead of the array of new heights.

A demo:

cuttingGrass([3, 4, 4, 4], 1, 1, 1) ➞ [[2, 3, 3, 3], [1, 2, 2, 2], "Done"]

// 1st cut shaves off 1: [3, 4, 4, 4] ➞ [2, 3, 3, 3]
// 2nd cut shaves off 1: [2, 3, 3, 3] ➞ [1, 2, 2, 2]
// 3rd cut shaves off 1: [1, 2, 2, 2] ➞ [0, 1, 1, 1], but one element reached zero so we return "Done".

Examples

cuttingGrass([5, 6, 7, 5], 1, 2, 1)
➞ [[4, 5, 6, 4], [2, 3, 4, 2], [1, 2, 3, 1]]

cuttingGrass([4, 4, 4, 4], 1, 1, 1, 1)
➞ [[3, 3, 3, 3], [2, 2, 2, 2], [1, 1, 1, 1], "Done"]

cuttingGrass([8, 9, 9, 8, 8], 2, 3, 2, 1)
➞ [[6, 7, 7, 6, 6], [3, 4, 4, 3, 3], [1, 2, 2, 1, 1], "Done"]

cuttingGrass([1, 0, 1, 1], 1, 1, 1) ➞ ["Done", "Done", "Done"]

Notes

• The number of lawn cuts is variable.
• There will be at least one cut.
• Return "Done" onwards for each additional cut if the grass has already been completely mowed (see fourth example).