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48 lines
1.0 KiB
48 lines
1.0 KiB
#include <bits/stdc++.h>
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using namespace std;
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int n;
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const int N = 110;
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int a[N];
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int cnt;
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bool st[N];
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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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for (int i = 1; i <= n; i++)
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printf("%d ", a[i]);
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cnt++;
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printf("\n");
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return;
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}
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for (int i = 2; i <= n; i++) {
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if (!st[i]) {
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bool f = false;
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if (isPrime(a[step - 1] + i)) {
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if (step < n)
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f = true;
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else if (isPrime(i + 1))
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f = true;
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}
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if (f) {
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st[i] = true;
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a[step] = i;
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dfs(step + 1);
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st[i] = false;
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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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a[1] = 1;
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dfs(2);
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printf("%d", cnt);
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return 0;
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} |