Makes nsieve fair. Solves #419

bench/algorithm/nsieve/3.cpp

@@ -0,0 +1,36 @@
+// The Computer Language Shootout
+// http://shootout.alioth.debian.org/
+// Precedent C entry modified by bearophile for speed and size, 31 Jan 2006
+// Converted to C++ by Paul Kitchin
+
+#include <iomanip>
+#include <iostream>
+#include <sstream>
+#include <vector>
+
+#include <iostream>
+#include <cmath>
+#include <vector>
+#include <algorithm>
+
+inline void nsieve(unsigned int limit) {
+    std::vector<bool> primes(limit + 1, true);
+    primes[1] = false;
+    unsigned int p = 2;
+    while (p <= static_cast<unsigned int>(std::sqrt(limit))) {
+        for (unsigned int i = p * p; i <= limit; i += p) {
+            primes[i] = false;
+        }
+        p = std::find(primes.begin() + p + 1, primes.end(), true) - primes.begin();
+    }
+    unsigned int primeCount = std::count(primes.begin(), primes.end(), true);
+    std::cout << "Primes up to " << std::setw(8) << limit << std::setw(9) << primeCount << '\n';
+}
+
+int main(int argc, char **argv) {
+    unsigned int n = (argc <= 1) ? 4 : std::atoi(argv[1]);
+    for (unsigned int i = n; i >= n - 2; --i) {
+        nsieve(10000 << i);
+    }
+    return 0;
+}

bench/bench_cpp.yaml

@@ -18,6 +18,7 @@ problems:
   - name: nsieve
     source:
       - 1.cpp
+      - 3.cpp
 compiler_version_command:
 compiler_version_regex:
 runtime_version_parameter: