Python : modular_exponential(代码)

def modularExponential(base, power, mod):
if power < 0:
return -1
base %= mod
result = 1

while power > 0:
	if power & 1:
		result = (result * base) % mod
	power = power >> 1
	base = (base * base) % mod
return result

def main():
print(modularExponential(3, 200, 13))

if name == ‘main’:
main()