## Solution(Python)
```Python
class Solution:
def subarraySum(self, nums: List[int], k: int) -> int:
return self.hashingCumulativeSumFrequecny(nums, k)
"""
Time Complexity: O(n^3)
Space Complexity: O(1)
"""
def bruteforce(self, nums: List[int], k: int) -> int:
cnt = 0
for i in range(len(nums)):
for j in range(i, len(nums)):
if sum(nums[i: j + 1]) == k:
cnt += 1
return cnt
"""
Time Complexity: O(n^2)
Space Complexity: O(n)
"""
def CumulativeSum(self, nums: List[int], k: int) -> int:
cnt = 0
n = len(nums)
CumSum = [0] * (n + 1)
CumSum[0] = 0
for i in range(1, n + 1):
CumSum[i] = CumSum[i - 1] + nums[i - 1]
for i in range(n):
for j in range(i + 1, len(nums) + 1):
if CumSum[j] - CumSum[i] == k:
cnt += 1
return cnt
"""
Time Complexity: O(n^2)
Space Complexity: O(1)
"""
def ConsecutiveSumOnthefly(self, nums: List[int], k: int) -> int:
n = len(nums)
cnt = 0
for i in range(n):
curSum = 0
for j in range(i, n):
curSum += nums[j]
if curSum == k:
cnt += 1
return cnt
"""
Time Complexity: O(n)
Space Complexity: O(n)
"""
def hashingCumulativeSumFrequecny(self, nums: List[int], k: int) -> int:
n = len(nums)
CumSum = 0
CumSumFreq = defaultdict(lambda: 0)
CumSumFreq[0] = 1 # by default sum with 0 is always going to be there
cnt = 0
for i in range(n):
CumSum += nums[i]
if CumSum - k in CumSumFreq:
cnt += CumSumFreq[CumSum - k]
CumSumFreq[CumSum] += 1
return cnt
```