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authorNguyễn Gia Phong <vn.mcsinyx@gmail.com>2019-12-15 15:09:13 +0700
committerNguyễn Gia Phong <vn.mcsinyx@gmail.com>2019-12-15 15:09:13 +0700
commit9e28e4c7b67c54229df11d355047ac8a88ea1817 (patch)
tree0d9d40db69613c2c49564a3f1987a005d61f4db3 /ntu/ngto4.c
parent67393f42f41ab92219deb549f711121c4dab845b (diff)
downloadcp-9e28e4c7b67c54229df11d355047ac8a88ea1817.tar.gz
Normalize pathname
Diffstat (limited to 'ntu/ngto4.c')
-rw-r--r--ntu/ngto4.c27
1 files changed, 27 insertions, 0 deletions
diff --git a/ntu/ngto4.c b/ntu/ngto4.c
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--- /dev/null
+++ b/ntu/ngto4.c
@@ -0,0 +1,27 @@
+#include <stdio.h>
+#include <math.h>
+
+#define idx(n) (n - 1) / 2 - 1
+
+long primes[1000000];
+
+int main()
+{
+	long i, j;
+	char pdict[500001] = {[0 ... 500000] = 1};
+	for (i = 3; i < 1000; i += 2)
+		if (pdict[idx(i)])
+			for (j = i * i; j < 1000000; j += i * 2)
+				pdict[idx(j)] = 0;
+
+	primes[0] = 2;
+	j = 0;
+	for (i = 3; i < 1000000; i += 2)
+		if (pdict[idx(i)])
+			primes[++j] = i;
+
+	printf("%ld ", primes[78497]);
+	printf("\n%ld\n", j);
+
+	return 0;
+}