interviewstreet

changing_bits.cpp

#include<stdio.h>
#include<string.h>
#include<ctype.h>
void inline polyadd(unsigned short int A[],unsigned short int B[],unsigned short int C[], int);
void inline display(unsigned short int A[],int);
void inline polyset(unsigned short int A[],int,int);
int main()
{
      unsigned short int A[6250]={0};
      unsigned short int B[6250]={0};
      unsigned short int C[6251]={0};
      unsigned short int mask=0,mask1=0;
      int n=0,q=0;char c;int i=0,size=0,coun_i=0;
      scanf("%d%d",&n,&q);
      //Reading the initial value of A & B
      getchar();int a_c=0,a_r=0;
      while((c=getchar())!='\n')
      {
               if(c=='1'){
                       mask1=1;
                       mask1=mask1<<a_c;
                       mask=mask|mask1;
                       mask1=0;
               }
               if(isdigit(c))               
		a_c++;
               if(a_c==16){
                       A[a_r++]=mask;
                       mask=0;
                       a_c=0;
               }



      }
      if(a_c!=0){
                       A[a_r]=mask;

      }

      i=0;a_r=0,a_c=0,mask=0,mask1=0;
      while((c=getchar())!='\n')
      {
               if(c=='1'){
                       mask1=1;
                       mask1=mask1<<a_c;
                       mask=mask|mask1;
                       mask1=0;
               }
		if(isdigit(c))               
		a_c++;
               if(a_c==16){
                       B[a_r++]=mask;
                       mask=0;
                       a_c=0;
               }
      }
      if(a_c!=0){
                       B[a_r]=mask;

      }

   char input[10];
       int index=0;
       int set=0,r_c=0;

    coun_i=0;
    while(coun_i<q)
    {
              scanf("%s",input);
              if(!strcmp("set_a",input))
              {       scanf("%d%d",&index,&set);
                      polyset(A,index,set);
                      r_c=0;

              }
              else if(!strcmp("set_b",input))
              {        scanf("%d%d",&index,&set);
                       polyset(B,index,set);
                       r_c=0;
              }
              else if(!strcmp("get_c",input))
              {        scanf("%d",&index);
                       if(r_c==0){
				C={0};
                               polyadd(A,B,C,n);
			}
                       display(C,index);
                       r_c=1;
              }
              else
              {}
              coun_i++;
      }

      return 0;
}
void polyset(unsigned short int A[6250],int index,int set)
{
       unsigned short a=0,b=0,c=0,d=0,f=0,set1=1,set2=65535;
       a=index/16; b=index%16; c=set;d=c<<b;
       f=A[a]&(set1<<b);
       if(!set)
          set2=set2^(set1<<b);
       if(f)
          A[a]=A[a]&set2;
       else
          A[a]=A[a]|d;
}

void polyadd(unsigned short int A[6250],unsigned short int B[6250],unsigned short int C[6251],int s)
{      unsigned int carry=0,i=0;
      int a=s/16+1;
      if(a>6250) a--;
      for(i=0;i<a;i++)
      {
              C[i]=(A[i]+B[i]+carry)%65536;
              carry=(A[i]+B[i]+carry)/65536;
      }
      if(carry && i==6250)
         C[i]=carry;

}


void display(unsigned short int A[6251],int index)
{      int a=0,b=0,c=0,d=0,f=0,set=1,k=0;
       a=index/16; b=index%16; c=set;d=c<<b;
	k=A[a];       
	f=k&d;
       if(f)
          printf("%d",1);
       else
          printf("%d",0);

}

The above code is failing for some 4 hidden test cases....could some body has any idea what could be it.