var input = [1]
// result
[{
    start: 'monday',
    end: 'monday'
}]

var input = [1,2,3,4,5,6,7]
// result
[{
    start: 'monday',
    end: 'sunday'
}]

var input = [1,2,3,5,6,7]
//result
[{
    start: 'monday',
    end 'wednesday'
},
{
    start: 'friday',
    end: 'sunday'
}]

var input = [1,2,4,6,7]
// result
[{
    start: 'monday',
    end 'tuesday'
},
{
    start: 'thursday',
    end: 'thursday'
},
{
    start: 'saturday',
    end: 'sunday'
}]