ural 1343. Fairy Tale打表

#include <iostream>
#include <sstream>
#include <fstream>
#include <string>
#include <vector>
#include <deque>
#include <queue>
#include <stack>
#include <set>
#include <map>
#include <algorithm>
#include <functional>
#include <utility>
#include <bitset>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cstdio>
#include <cstring>
#define FOR(i, a, b)  for(int i = (a); i <= (b); i++)
#define RE(i, n) FOR(i, 1, n)
#define FORP(i, a, b) for(int i = (a); i >= (b); i--)
#define REP(i, n) for(int i = 0; i <(n); ++i)
#define SZ(x) ((int)(x).size )
#define ALL(x) (x).begin(), (x.end())
#define MSET(a, x) memset(a, x, sizeof(a))
using namespace std;


typedef long long int ll;
typedef pair<int, int> P;
int read(){
    int x=0,f=1;char ch=getchar();
    while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
    while(ch>=‘0‘&&ch<=‘9‘){x=x*10+ch-‘0‘;ch=getchar();}
    return x*f;
}
const double pi=3.14159265358979323846264338327950288L;
const double eps=1e-6;
const int mod = 1e9 + 7;
const int INF = 0x3f3f3f3f;
const int MAXN = 1e7;
const int xi[] = {0, 0, 1, -1};
const int yi[] = {1, -1, 0, 0};

int N, T;
int prime[MAXN+10], cnt = 0;
int a[MAXN+10];

void init(){
    for(int i = 2; i <= MAXN; i++) a[i] = true;
    for(int i = 2; i <= MAXN; i++){
        if(a[i]){
            prime[++cnt] = i;
        }
        for(int j = 1; j <= cnt; j++){
            if(prime[j]*i > MAXN) break;
            a[prime[j]*i] = false;
            if(i%prime[j] == 0) break;
        }
    }
}

int main() {
    //freopen("in.txt", "r", stdin);
    int n;
    init();
    ll x, y = 1;
    cin >> n;
    if(n == 0){
        printf("000000000003\n");
        exit(0);
    }
    cin >> x;
    if(n == 12) {
        printf("%012I64d\n", x);
        exit(0);
    }
    for(int i = n; i < 12; i++) y *= 10;
    //cout << y << endl;
    //cout << y*x+1 <<" " <<y*(x+1) << endl;
    for(ll i = y*x+3; i < y*(x+1); i += 2){

        int flag = 1;
        for(int j = 1; j <= cnt  && prime[j] < i; j++){
            if(i%prime[j] == 0){
                flag = 0;
                break;
            }
        }
       // cout << i << endl;
        if(flag){
            printf("%012I64d\n", i);
            break;
        }
    }
    return 0;
}