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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.
Example 1:
Input: arr = [1,2], k = 3 Output: 9
Example 2:
Input: arr = [1,-2,1], k = 5 Output: 2
Example 3:
Input: arr = [-1,-2], k = 7 Output: 0
Constraints:
1 <= arr.length <= 10^51 <= k <= 10^5-10^4 <= arr[i] <= 10^4
To give you an array of integers arr and an integer k.
First of all, we need to make changes to the array, that is, the original array arr repeat k times.
For instance, if
arr = [1, 2]andk = 3, then after the array is modified[1, 2, 1, 2, 1, 2].
Then, you return to the largest array of sub-arrays in the revised and.
Note that the length may be sub-arrays 0, its sum is also in this case 0.
As a result may be large, so it is necessary mode (mod) 10^9 + 7 and then return.
Example 1:
Input: arr = [1,2], k = 3 Output: 9
Example 2:
Input: arr = [1, -2,1] , k = 5 Output: 2
Example 3:
Input: arr = [-1, -2] , k = 7 Output: 0
prompt:
1 <= arr.length <= 10^51 <= k <= 10^5-10^4 <= arr[i] <= 10^4