Wow!

You use length to index, that is how I did it since I figured it would be faster than back

dude that is amazing we have thought in the same solution with the same writing even with the same names 👌❤

thanks a lot! :)

Instead custom lambda, you can use predefined std::multiplies()

dude became crazy while coding lmao

Not sure why Clever has more upvotes, this one is definitely Best Practice.
I think it was more to do with how succinct the solution is.
Well done.

Technically, no.
string::npos is the preferred usage though

Impressive it all fit on one line
Usually hard to achieve with C++

daww the heart is cute <3

This is definitely the clearest and easiest to read solution

Do you and your friends a favor and put line 5 on more than one line. This is no fun to read.

Your are repeating the expression res += a + " ";
The code can be smaller.

needs more gooooools