start = 0

end = 1
2 3 4 5
end = 2
3 4 5
end = 3
4 5
end = 4
5
end = 5

start = 1

end = 2
3 4 5
end = 3
4 5
end = 4
5
end = 5

start = 2

end = 3
4 5
end = 4
5
end = 5

start = 3

end = 4
5
end = 5