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subArraysThatSumToK.py
32 lines (29 loc) · 1.01 KB
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subArraysThatSumToK.py
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"""
Given an unsorted array of integers (positive and negative numbers),
find all subarrays which adds to a given number K.
Time Complexity is O(n) and Space Complexity is O(n)
"""
class SubArraysThatSumToK(object):
def __init__(self, arr, K):
self.arr = arr
self.length = len(self.arr)
self.K = K
def findAllSubArrays(self):
sumHash = {}
sumHash[0] = [-1]
sumFromBegin = 0
for i in range(self.length):
sumFromBegin += self.arr[i]
if (sumFromBegin-self.K) in sumHash:
startIndices = sumHash[sumFromBegin-self.K]
for start in startIndices:
print "Subarray from indices " + str(start+1) + " to " + str(i)
indices = []
if sumFromBegin in sumHash:
indices = sumHash[sumFromBegin]
indices.append(i)
sumHash[sumFromBegin] = indices
arr = [10, 2, 22, 20, 10]
K = 24
subArrays = SubArraysThatSumToK(arr, K)
subArrays.findAllSubArrays()