You are given two non-negative integers a and b, at least one of which is positive.
Return their greatest common divisor: the largest positive integer that divides both a and b with no remainder.
By convention, when one value is 0 the result is the other value, so greatest_common_divisor(0, b) returns b.
NOTE: This is a function-type question — you only write the function. Do not read input or print anything; a hidden checker calls your function and checks its return value.
Arguments
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Returns
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