VA
Size: a a a
VA
AD
AD
v
IM
AD
VA
v
AD
G
w
AG
arr.map.with_index { |item, i| arr[0..i] }
Array.new(arr.size) { |i| arr[0..i] }
AD
Array.new(arr.size) { |i| arr[0..i] }
SM
arr = [1, 2, 3, 4]
arr.SOMETHING #=> [[1], [1,2], [1,2,3], [1,2,3,4]]
[1,2,3,4].each_with_object([]).map { |i, arr| arr.push(i).dup }
MS
MS
r
MS
AG