what is the fastest way to compute the greatest common divisor of n numbers?
Without recursion:
int result = numbers[0];
for(int i = 1; i < numbers.length; i++){
result = gcd(result, numbers[i]);
}
return result;
For very large arrays, it might be faster to use the fork-join pattern, where you split your array and calculate gcds in parallel. Here is some pseudocode:
int calculateGCD(int[] numbers){
if(numbers.length <= 2){
return gcd(numbers);
}
else {
INVOKE-IN-PARALLEL {
left = calculateGCD(extractLeftHalf(numbers));
right = calculateGCD(extractRightHalf(numbers));
}
return gcd(left,right);
}
}