What's wrong with my program???
#include <iostream>
using namespace std;

pair<int,int> FindAnswer(const char *arr, const int &N, const int K);

int main(void)
{
   // Inputs data
   int N, K;
   (cin >> N >> K).get();
   // Creates an extra array
   char *arr=new char[N];
   int length=0;
   int pos=-1;
   pair<int,int> res(-1,-1);
   char ch[1];
   while(pos!=N-1)
   {
      while(pos!=N-1 && cin.read(ch, 1) && cin)
      {
         // Reads the next character
         if(ch[0]=='\n')
            continue;
         ++pos;
         // Inserts the digit to the array
         if(ch[0]!='*')
            arr[length++]=ch[0];
         // Resets the array and finds the result
         else
         {
            if(length>=K)
            {
               pair<int,int> tmp=FindAnswer((const char *)arr, length, K);
               if(tmp.first<res.first)
               {
                  res.first=tmp.first;
                  res.second=pos-length+tmp.second;
               }
            }
            length=0;
         }
      }
   }
   // Outputs the result
   if(res.second==-1)
      cout << 0 << endl;
   else
      cout << res.second+1 << endl;
   return 0;
}
// Function determines the result
pair<int,int> FindAnswer(const char *arr, const int &N, const int K)
{
   int best=0;
   int res=0;
   int i;
   for(i=0; i<K; ++i)
      best+=arr[i]-'0';
   int prev=best;
   for(i; i<N; ++i)
   {
      int tmp=prev-arr[i-K]+arr[i];
      if(tmp<best)
      {
         best=tmp;
         res=i-K+1;
      }
      prev=tmp;
   }
   return make_pair(best, res);
}

Edited by author 14.03.2007 16:08

If you have WA#3 try to use this simple test:
1 1
9
Right answer is "1", of course.