Given an integer array arr and an integer k , modify the array by repeating it k times.
For example, if arr = [1, 2] and k = 3 then the modified array will be [1, 2, 1, 2, 1, 2] .
Return the maximum sub-array sum in the modified array. Note that the length of the sub-array can be 0 and its sum in that case is 0 .
As the answer can be very large, return the answer modulo 10 ^9 + 7 .
1 <= arr.length <= 10 ^51 <= k <= 10 ^5-10 ^4 <= arr[i] <= 10 ^4