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# 1191. K-Concatenation Maximum Sum
"""
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 1e9+7
"""
class Solution(object):
def max_sum(self, arr):
curr_max, max_end = int("-inf"), 0
for i in arr:
max_end += i
if max_end < 0:
max_end = 0
curr_max = max(curr_max, max_end)
return curr_max
def kConcatenationMaxSum(self, arr, k):
"""
:type arr: List[int]
:type k: int
:rtype: int
"""
total = sum(arr)
kadane = self.max_sum(arr)
if k < 2:
return kadane(10**9 + 7)
if total > 0:
return (kadane + (k - 1) * total) % (10**9 + 7)
double = self.max_sum(arr * 2)
return double % (10**9 + 7)
if __name__ == "__main__":
obj = Solution()
print(obj.kConcatenationMaxSum(arr=[1, 2], k=3))
print(obj.kConcatenationMaxSum(arr=[1, -2, 1], k=5))
print(obj.kConcatenationMaxSum(arr=[1, -2, 1], k=5))
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