From ab40629bd9914612aa869be23fa360a5dcd25929 Mon Sep 17 00:00:00 2001
From: Reiner Herrmann <reiner@reiner-h.de>
Date: Wed, 22 Sep 2010 21:32:38 +0200
Subject: projecteuler solution 187

---
 src/projecteuler/187.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 src/projecteuler/187.c

diff --git a/src/projecteuler/187.c b/src/projecteuler/187.c
new file mode 100644
index 0000000..a2e552e
--- /dev/null
+++ b/src/projecteuler/187.c
@@ -0,0 +1,30 @@
+#include "common.h"
+#include <stdlib.h>
+#include <string.h>
+
+// TODO: works only on 64 bit systems
+
+const unsigned long limit = 100000000;
+
+int main(void)
+{
+	unsigned long* p = primes(limit/2); // sqrt(limit)
+	unsigned long pcount = p[0];
+	unsigned long rcount = 0;
+	unsigned long i1, i2;
+	
+	for(i1=1; i1<=pcount; i1++)
+		for(i2=i1; i2<=pcount; i2++)
+		{
+			unsigned long result = p[i1] * p[i2];
+			if(result >= limit)
+				break;
+			rcount++;
+		}
+
+	printf("%li\n", rcount);
+
+	free(p);
+	return 0;
+}
+
-- 
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