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| -rw-r--r-- | challenge-192/james-smith/README.md | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/challenge-192/james-smith/README.md b/challenge-192/james-smith/README.md index b2d3bc04fb..7c47f95f78 100644 --- a/challenge-192/james-smith/README.md +++ b/challenge-192/james-smith/README.md @@ -54,7 +54,26 @@ We use `tr` with the `r` option to return the result of the translation... ### Performance... -Well this is where Perl is uber fast when it comes to strings - the string solution is faster than the bit manipulation. This is probably due to the overhead of each separate operation in the numeric version. +Well this is where Perl is uber fast when it comes to strings - the string solution is faster than the bit manipulation. This is probably due to the overhead of each separate operation in the numeric version. For a test example of "12345678" (`1011 1100 0110 0001 0100 1110`) the string method is 8x faster than the binary method. + +### Let's try again... + +Annoyed with the fact the elegant {bit operator based} solution is slower than the "hacky" string one - let's revisit the code using inline C - effectively it is EXACTLY the same algortihm as our first perl method. + +```C +int c_flip(int n) { + int r=0; + int k=0; + while(n) { + r|=(1^n&1)<<k++; + n>>=1; + } + return r; +} +``` + +Now - when comparing this to the other two: The C version is 4.5 times faster than the string version OR 35x faster than the equivalent Perl version. + # Task 2 - Equal Distribution |