20 lines
446 B
C++
20 lines
446 B
C++
#include <bits/stdc++.h>
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using namespace std;
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const int N = 1000000;
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int check[N];//元素值为0代表是素数
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int prime[N];
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int main() {
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int cnt = 0;
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for (int i = 2; i < N; i++) {
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//如果是素数
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if (!check[i]) prime[cnt++] = i;
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//筛出成倍的合数
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for (int j = 2 * i; j < N; j += i) check[j] = 1;
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}
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printf("%.2f", (double) clock() / CLOCKS_PER_SEC);
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return 0;
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}
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