added usage comment for MAX constant. i switched between 1000 for tes…

…ting, 40,000 for benchmarking. 195,100 to reach #5 on the leaderboard :)

README

@@ -15,7 +15,18 @@ Write a code in whichever language you are comfortable with to print as many pri
 //  40000 elapsed: 0.194436, by studying upper bounds of max prime factor (was 691 for 40,000)
 //  TODO: use log/exp/proportions to give a lower number for 40,000 , higher number for 1000
 
-Written in xcode
+/**
+ * How many primes are you trying to find. useful to target which spot you want 
+ * to get on the leaderboard. Made it to #5 with the last commit
+ *
+ * For benchmarking flip to 40,000
+ * For testing, flip to http://primes.utm.edu/lists/small/1000.txt and compare last
+ * For making it to #5 on the leaderboard on http://hackerrank.com, flipped to 195100 :)
+ */
+
+See main.c for actual code. written on a mac, on a weekend dedicated to C/C++.
+
+Found this puzzle on http://hackerrank.com ( this solution hit #5 in the leaderboard finding 195101 primes )
 
 ~B
 

primes/main.c

@@ -1,6 +1,6 @@
 //
 //  main.c
-//  primes
+//  primes - a weekend c exercise
 //
 //  NOTES
 //  40,000 elapsed: 13.410259 by skipping even numbers
@@ -20,7 +20,15 @@
 #include <stdlib.h>
 #include <time.h>
 
-#define MAX 1000
+/**
+ * How many primes are you trying to find. useful to target which spot you want 
+ * to get on the leaderboard. Made it to #5 with the last commit
+ *
+ * For benchmarking flip to 40,000
+ * For testing, flip to http://primes.utm.edu/lists/small/1000.txt and compare last
+ * For making it to #5 on the leaderboard on http://hackerrank.com, flipped to 195100 :)
+ */
+#define MAX 40000
 int bitmap[MAX];
 int _index=0;
 int _max_factor=0;
@@ -34,8 +42,6 @@ isPrime(int m){
             //printf("\n\tis %d %% %d = %d ? so %d is not prime",m,bitmap[i], m % bitmap[i], m / bitmap[i]);
             _max_factor = (_max_factor<n)?n:_max_factor;
             res=0;break;
-        }else{
-
         }
         if(n > MAX/10){
             break;