URAL1057[Amount of degrees]

无语，WA了很多次，出错的地方分别是精度，还有就是两句同样的错误。

思路是找出比X小的数一共有几个，再找出不超过Y的数一共有几个，然后相减得答案。

CODE:

/*

PROGRAM: $PROGRAM

AUTHOR: Su Jiao

DATE: 2010-3-28

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

{

      typedef long long int Type;

      Type X,Y;

      int K,B;

      static Type C(Type n,Type m)

      {

             if (m<0||m>n) return 0;

             Type c=1;

             for (int i=m+1;i<=n;i++) c=c*i/(i-m);

             return c;

      }

      public:

      Application()

      {

                   cin>>X>>Y

                      >>K

                      >>B;

      }

      int run()

      {

          vector<Type> b;

          b.push_back(1);

          while (b.back()*B<=Y) b.push_back(b.back()*B);

         

          Type min=0,max=0;

          vector<bool> min_state(b.size(),false),max_state(b.size(),false);

          int counter;

         

          counter=0;

          for (int i=b.size()-1;i>=0;i–)

              if (min+b[i]<X&&counter<K) min+=b[i],counter++,min_state[i]=true;

          counter=0;

          for (int i=b.size()-1;i>=0;i–)

              if (max+b[i]<=Y&&counter<K) max+=b[i],counter++,max_state[i]=true;

         

          Type min_index=1,max_index=1;

          counter=K;

          for (int i=min_state.size()-1;i>=0;i–)

              if (min_state[i]) min_index+=C(i,counter–);

          if (counter) min_index–;

          counter=K;

          for (int i=max_state.size()-1;i>=0;i–)

              if (max_state[i]) max_index+=C(i,counter–);

          if (counter) max_index–;

          cout<<max_index-min_index<<endl;

         

          return 0;

      }

};

 

int main()

{

    Application app;

    return app.run();

}