URAL1032[Find a multiple]

开始做了个O(n^2)的DP，但是WA#33，我改了，还是WA，重写，还是WA。无语到了极点。

后来还是用O(n)的算法做了（提示：需要用到抽屉原理）。

CODE:

/*

PROGRAM: $PROGRAM

AUTHOR: Su Jiao

DATE: 2010-3-20

DESCRIPTION:

$DESCRIPTION

*/

#include <iostream>

using std::cin;

using std::cout;

#include <fstream>

using std::ifstream;

using std::ofstream;

#include <sstream>

using std::stringstream;

using std::endl;

#include <vector>

using std::vector;

#include <string>

using std::string;

#include <stack>

using std::stack;

#include <queue>

using std::queue;

#include <set>

using std::set;

#include <map>

using std::map;

using std::pair;

using std::make_pair;

#include <algorithm>

using std::sort;

#include <cassert>

//using std::assert;

 

class Application

{

      int N;

      vector<int> a;

      public:

      Application()

      {

                    cin>>N;

                    a.resize(N);

                    for (int i=0;i<N;i++) cin>>a[i];

      }

      int run()

      {

          static const int NOTIN=-1;

          vector<int> sum(N+1);

          sum[0]=0;

          for (int i=0;i<N;i++)

              sum[i+1]=sum[i]+a[i];

          vector<int> counter(N,NOTIN);

          for (int i=0;i<=N;i++)

          {

              if (counter[sum[i]%N]!=NOTIN)

              {

                 cout<<i-counter[sum[i]%N]<<endl;

                 for (int j=counter[sum[i]%N];j<i;j++)

                     cout<<a[j]<<endl;

                 break;

              }

              else counter[sum[i]%N]=i;

          }

          return 0;

      }

};

 

int main()

{

    Application app;

    return app.run();

}