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#!/opt/local/bin/gawk
#
# See ../README.md
#
#
# Run as: gawk -f ch-1.gawk < input-file
#
#
# Find the GCD, using Stein's algorithm
# (https://en.wikipedia.org/wiki/Binary_GCD_algorithm)
#
function gcd (u, v, u_odd, v_odd) {
u_odd = u % 2
v_odd = v % 2
return u == v || !v ? u \
: !u ? v \
: !u_odd && !v_odd ? lshift (gcd(rshift (u, 1), rshift (v, 1)), 1) \
: !u_odd && !v_odd ? gcd(rshift (u, 1), v) \
: !u_odd && !v_odd ? gcd(u, rshift (v, 1)) \
: u > v ? gcd(u - v, v) \
: gcd(v - u, u)
}
function is_power_of_n (number, n) {
return number < 1 ? 0 \
: number == 1 ? 1 \
: number % n ? 0 \
: is_power_of_n(number / n, n)
}
function is_power_of_2 (number) {
return is_power_of_n(number, 2)
}
$1 % 2 || $2 % 2 {
print 0
next
}
{
r = gcd($1, $2)
print (r > 1 && is_power_of_2(r) ? 1 : 0)
}
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