forked from OSchip/llvm-project
52 lines
1.1 KiB
C++
52 lines
1.1 KiB
C++
//===----------------------------------------------------------------------===//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is dual licensed under the MIT and the University of Illinois Open
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// Source Licenses. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// REQUIRES: long_tests
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// Not a portable test
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// <__hash_table>
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// size_t __next_prime(size_t n);
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// If n == 0, return 0, else return the lowest prime greater than or equal to n
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#include <__hash_table>
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#include <cassert>
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bool
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is_prime(size_t n)
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{
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switch (n)
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{
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case 0:
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case 1:
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return false;
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}
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for (size_t i = 2; i*i <= n; ++i)
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{
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if (n % i == 0)
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return false;
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}
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return true;
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}
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int main()
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{
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assert(std::__next_prime(0) == 0);
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for (std::size_t n = 1; n <= 100000; ++n)
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{
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std::size_t p = std::__next_prime(n);
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assert(p >= n);
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for (std::size_t i = n; i < p; ++i)
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assert(!is_prime(i));
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assert(is_prime(p));
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}
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}
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