https://www.codechef.com/viewsolution/29849687

I used binary exponentiation to compute 2^n

# Wa in NXS3

your power function is wrong

```
long long int modpower(long long int b,long long int po, long long int p){
long long int ans=1;
while(po){
if(po%2){
ans*=b;
ans%=p;
}
b*=b;
b%=p;
po/=2;
}
return ans;
}
```

It returns b^{po} mod p

Here’s my exponentiation function template

in one line:

`inline ll powmod(ll a,ll b,ll mod) {ll res=1;a%=mod; for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}`

That doesn’t look like one line to me

ok…a bit forced I know. By the way…your template have a problem. What’s the output for this?

b= 1e18

po =10

p=1e9+7

I do b%p before putting it in so…

Also I just checked, he solved the question 19 hours ago

Never mind the test cases are visible now.

Thanks for pointing out everyone i realised that i made a mistake after some time in my power function

i was reading, not an easy cake. I coud see your code failed in this testcase for example

7

20 55 81 6 22 50 93

I forgot to insert 0th element in map.

And still it passes pretests as well as ~20 test cases

Thanks