USACO Section 1.5: Superprime Rib

 1 /*

 2 ID: leetcod3

 3 PROG: sprime

 4 LANG: C++

 5 */

 6 #include <iostream>

 7 #include <fstream>

 8 #include <string>

 9 #include <map>

10 #include <vector>

11 #include <set>

12 #include <algorithm>

13 #include <queue>

14 #include <cmath>

15 #include <list>

16 #include <cstring>

17 #include <cstdlib>

18 #include <limits>

19 #include <stack>

20 

21 using namespace std;

22 

23 ofstream fout ("sprime.out");

24 ifstream fin ("sprime.in");

25 

26 vector<int> ans;

27 int N;

28 

29 bool prime(int x) {

30     if (x == 2) return true;

31     for (int i = 2; i <= (int)sqrt(x*1.0); i++) {

32         if (x % i == 0) return false;

33     }

34     return true;

35 }

36 

37 void dfs(int x, int cur) {

38     if (cur == N) {

39         ans.push_back(x);

40         return;

41     }

42     for (int i = 1; i < 10; ++i) {

43         int tmp = x*10;

44         tmp += i;

45         if (prime(tmp)) dfs(tmp, cur+1);

46     }

47 }

48 

49 int main()

50 {

51     fin >> N;

52     for (int i = 2; i < 10; ++i) {

53         if (prime(i)) dfs(i, 1);

54     }

55     sort(ans.begin(), ans.end());

56     for (int i = 0; i < ans.size(); i++) fout << ans[i] << endl;

57     return 0;

58 }