Modular Exponentiation

#1

Why most of the test cases I am failing ??

#2

It’s because this is not how modular exponentiation is implemented .
Please refer this link and understand what modular exponentiation is https://www.hackerearth.com/practice/math/number-theory/basic-number-theory-1/tutorial/

#3

Ok but if we do (a+b)%mod or (a%mod+b%mod)%mod in both the cases ans will be same then why my code is incorrect ??

#4

Yeah but your answer is incorrect because of the overflow.
pow(a,b) returns garbage value because of integer overflow

#5

https://ide.codingblocks.com/s/224195 please help me to correct this code

#6

Change line 6 to int last_bit=(p&1);
and use long int.
Then your code works fine.