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53 lines
754 B
53 lines
754 B
#include<bits/stdc++.h>
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using namespace std;
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//常规法
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bool isPrime(int n) {
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if (n <= 3) {
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return n > 1;
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}
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for(int i = 2; i < n; i++) {
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if (n % i == 0) {
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return false;
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}
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}
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return true;
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}
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// 平方根法优化
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bool isPrimeSqrt(int n) {
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if (n <= 3) {
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return n > 1;
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}
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int s = sqrt(n);
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for (int i = 2; i <= s; i++) {
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if(n % i == 0) {
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return false;
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}
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}
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return true;
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}
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//6x优化法
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bool isPrime6x(int n) {
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if (n <= 3) {
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return n > 1;
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}
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if (n % 6 != 1 && n % 6 != 5) {
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return false;
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}
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int s= sqrt(n);
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for (int i = 5; i <= s; i += 6) {
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if (n % i == 0 || n % (i + 2) == 0) {
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return false;
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}
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}
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return true;
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}
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int main() {
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cout<<isPrime(131)<<endl;
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cout<<isPrimeSqrt(131)<<endl;
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cout<<isPrime6x(131)<<endl;
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return 0;
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}
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