instructions.md

You're an avid bird watcher that keeps track of how many birds have visited your garden in the last seven days.

You have six tasks, all dealing with the numbers of birds that visited your garden.

1. Check what the counts were last week

For comparison purposes, you always keep a copy of last week's counts nearby, which were: 0, 2, 5, 3, 7, 8, and 4. Define the lastWeek binding that contains last week's counts:

lastWeek
// => [| 0; 2; 5; 3; 7; 8; 4 |]

2. Check how many birds visited yesterday

Implement the yesterday function to return how many birds visited your garden yesterday. The bird counts are ordered by day, with the first element being the count of the oldest day, and the last element being today's count.

yesterday [| 3; 5; 0; 7; 4; 1 |]
// => 4

3. Calculate the total number of visiting birds

Implement the total function to return the total number of birds that have visited your garden:

total [| 3; 5; 0; 7; 4; 1 |]
// => 20

4. Check if there was a day with no visiting birds

Implement the dayWithoutBirds function that returns true if there was a day at which zero birds visited the garden; otherwise, return false:

dayWithoutBirds [| 3; 5; 0; 7; 4; 1 |]
// => true

5. Increment today's count

Implement the incrementDayCount function to increment today's count and return the updated counts:

let birdCount = [| 3; 5; 0; 7; 4; 1 |]
incrementDayCount birdCount
// => [| 3; 5; 0; 7; 4; 2 |]

6. Check for odd week

Over the last year, you've found that some weeks for the same, odd pattern, where the counts alternate between one and zero birds visiting. Implement the oddWeek function that returns true if the bird count pattern of this week matches the odd pattern:

oddWeek [| 1; 0; 1; 0; 1; 0; 1 |]
// => true