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52 lines
1.0 KiB
52 lines
1.0 KiB
#include <bits/stdc++.h>
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using namespace std;
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const int N = 100;
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int n;
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int cnt;
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int st[N];
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vector<int> path;
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//判断一个数是不是质数
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bool isPrime(int x) {
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if (x < 2) return false;
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for (int i = 2; i <= x / i; i++)
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if (x % i == 0) return false;
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return true;
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}
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void dfs(int step) {
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if (step == n + 1) {
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if (isPrime(1 + path.back())) {
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cnt++;
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for (int i = 0; i < path.size(); i++)
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cout << path[i] << " ";
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cout << endl;
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}
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return;
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}
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//摆放当前位置数字
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for (int i = 2; i <= n; i++) {
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if (!st[i]) {
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if (isPrime(i + path.back())) {
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path.push_back(i);
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st[i] = true;
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dfs(step + 1);
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st[i] = false;
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path.pop_back();
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}
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}
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}
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}
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int main() {
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cin >> n;
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//素数环从1开始
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path.push_back(1);
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st[1] = true;
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dfs(2);
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cout << cnt << endl;
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return 0;
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}
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