DailyCoding/Day_54.py at master · iamakkkhil/DailyCoding · GitHub

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"""
DAY 54 : Zero Sum Subarrays.
https://www.geeksforgeeks.org/find-the-largest-subarray-with-0-sum/

QUESTION : You are given an array arr[] of size n. Find the total count of sub-arrays
having their sum equal to 0.

Expected Time Complexity : O(n)
Expected Auxilliary Space : O(n)

Constraints:
1<= n <= 10^7
-10^10 <= arr[i] <= 10^10

"""

def findSubArrays(arr,n):
    sum_ = 0
    sum_same = {}
    zero_sum = 0
    for i in range(n):
        sum_ += arr[i]
        if sum_ == 0:
            zero_sum += 1
        if sum_ not in sum_same.keys():
            sum_same[sum_] = [i]
        else:
            sum_same[sum_].append(i)
            num = len(sum_same[sum_])
            zero_sum += num-1

    return zero_sum


n = 6
arr = [0,0,5,5,0,0]
findSubArrays(arr, n)