how to optimise my code to make execute in<0.612 sec

Question

actually, i have take a test, online. my program is correct and passed all test cases but unfortunately, i couldn't submit my code.

the below program is to find the nearest power of number 'a' and the resultant answer should be less than or equal to 'b'

example:

2^3=8 #here, a is 2 and b is 8.

the logic is below...

def nearestPower(a,b):
i=int(0)
x=int(1)
for x in range(int(b/2)):
n=pow(a,x)
if(pow(a,x)<=b):
rem=int(n)
return rem.

in output box:

your program took more time than expected.
Expected time limit<0.612 sec.
Hint: please optimise your code..

(my opinion:
my code took more time due to range() in for loop.)

how to optimise my code:

Answer 1

I tried all your opinions but unfortunately nothing worked,and finally i unlocked the solution.

this is it.

def nearestPower(a,b):
x=math.floor(math.log(b,a))
xPlusOne=x+1
number1=a**x
number2=a**xPlusOne
if(abs(number1-b)>abs(number2-b)):
return number2
else:
return number1

Thank you for your help and support

Answer 2

Using your code i did some small changes and compared speed in relation to the original code:

def nearestPower(a,b):
for x in range(b // 2):
n = pow(a, x)
if n <= b:
return n

nearestPower(2,8)

speed is:

vesion original 0:00:00.638562
revised code 0:00:00.161031

Answer 3

~swim~

It was an contest question while submitting the solution, it calculates the time (built in constraints), by that we wil come to know the time.

Answer 4

Thank you for all your answers....

Answer 5

This is my recursive implementation. Can you test to see if it's faster?

https://code.sololearn.com/ceia86qzJXLa/?ref=app

Answer 6

Try this, maybe it can perform a little better ...

def nearestPower(a, b):
c ,p, x = 0, 1, 0
while True:
c = pow(a, x)
if c > b:
return p
p = c
x += 1

Answer 7

Ipang, I dont think it will. Itll run longer. I think ✨Sujithra💫 should use the for loop, but only up to the square root of b

Answer 8

Thomas Williams
Maybe, I just tried it with the example (a=2, b=8), didn't run any benchmark, just a test run on Playground : )

Answer 9

Ipang I have no doubt that itll work. I just think that limiting the loop even more would work better :)

Answer 10

Thomas Williams
Yes I understand what you mean. I haven't looked into adding more break conditions into that loop.

Thanks for reminding me about it Thomas 👍

Answer 11

The time it takes to execute any code depends on the power of the machine it's being run on..