usaco-sprime-superprime-pass

这个题目开始真正用C＋＋了，因为，数组的分配有限制了，只好用c++中的vector:

/*
ID: qq104801
LANG: C++
TASK: sprime
*/

#include <iostream>
#include <cstdio>
#include <string>
#include <cstring>
#include <vector>
#include <map>
#include <set>
#include <algorithm>
#include <cstdlib>
#include <cmath>

using namespace std;

vector<vector<int> > p(9);
int n;

int isprime(int x)
{    
    if (x%2==0)return 0;
    for(int i=3;i*i<=x;i+=2)
        if(x%i==0)return 0;    
    return 1;
}

void test()
{    
    freopen("sprime.in","r",stdin);
    freopen("sprime.out","w",stdout);
    cin>>n;
    //cout<<n<<endl;
    p[1].push_back(2);
    p[1].push_back(3);
    p[1].push_back(5);
    p[1].push_back(7);
    for(int i=2;i<=n;i++)
    {
        for(int j=0;j<p[i-1].size();j++)
        {
            long long num=p[i-1][j]*10;
            long long k;
            for(k=num+1;k<=num+9;k+=2)
                if(isprime(k))p[i].push_back(k);
        }
    }

    for(int i=0;i<p[n].size();i++)
        cout<<p[n][i]<<endl;
}

int main () 
{        
    test();        
    return 0;
}

看看测试结果：

USER: cn tom [qq104801]
TASK: sprime
LANG: C++

Compiling...
Compile: OK

Executing...
   Test 1: TEST OK [0.008 secs, 3508 KB]
   Test 2: TEST OK [0.003 secs, 3508 KB]
   Test 3: TEST OK [0.008 secs, 3508 KB]
   Test 4: TEST OK [0.008 secs, 3508 KB]
   Test 5: TEST OK [0.011 secs, 3508 KB]

All tests OK.

Your program ('sprime') produced all correct answers! This is your submission #2 for this problem. Congratulations!

Here are the test data inputs:

------- test 1 ----
4
------- test 2 ----
5
------- test 3 ----
6
------- test 4 ----
7
------- test 5 ----
8

Keep up the good work!
Thanks for your submission!