Google Interview Question for SDE1s


Country: United States




Comment hidden because of low score. Click to expand.
0
of 0 vote

# how to keep track of the sum in a sliding window for
# the data that are on disk
# rather than memory
# may 11 2017

from itertools import islice

def window(seq, n=2):
    it = iter(seq)
    result = tuple(islice(it,n))
    if len(result) == n:
        yield result
        sum_windows = sum(result)
        for elem in it:
            result = result[1:] + (elem,)
            # i believe this is what google is looking for
            sum_windows += elem
            print('The sum of the window is ', sum_windows)
            yield result

for x in window(range(10),4):
    print(x)

- an idea but its a bit slow May 19, 2017 | Flag Reply
Comment hidden because of low score. Click to expand.
0
of 0 vote

When it means data is on disk, it means that size of the data is not known and is probably very large. Like a 1GB file. In such case we can used a circular buffer (circular linked list say size N) to read a chunk of data in the buffer and slide the window of size k to get the sum. As we reach the end of buffer, we can read N-K chunk of data in the buffer and keep adding the data in head to the sliding window.

- Anonymous March 15, 2018 | Flag Reply


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