Next Palindrome SPOJ (PALIN) - c

Question

While solving the NEXT PALINDROME question on SPOJ. I have considered for every possible case and wrote the code. But it is showing WA(Wrong Answer). I am not getting my mistake or any possible case where my code won't work.
Below is my code.
Please help me out.
Thank You.
#include<stdio.h>
#include<string.h>
char K[10000000];
int a[10000000];
int main()
{
int t,length,i,count,j,rem,carry;
scanf("%d",&t);
while(t--)
{
scanf("%s",K);
length=strlen(K);
count=0;
for(i=0;i<length;i++)
{
a[i]=K[i]-'0';
if(a[i]==9)
count++;
}
if(length==2 && count!=length)
{
if(a[0]<=a[1])
{
a[1]=++a[0];
}
else
{
a[1]=a[0];
}
for(i=0;i<length;i++)
{
printf("%d",a[i]);
}
printf("\n");
continue;
}
if(count==length)
{
if(length==1)
{
printf("11\n");
continue;
}
memset(a,0,sizeof(a));
a[0]=10;
a[length-1]=1;
for(i=0;i<length;i++)
{
printf("%d",a[i]);
}
printf("\n");
continue;
}
i=0;
j=length-1;
count=0;
while(j-i!=1 && j-i!=0)
{
if(a[i]>a[j])
{
a[j--]=a[i++];
count++;
}
else
{
if(a[i]<a[j])
count--;
a[j--]=a[i++];
}
}
if(count==0)
{
rem=a[i]+1;
a[i]=rem%10;
a[j++]=a[i--];
carry=rem/10;
while(carry!=0)
{
rem=a[i]+1;
a[i]=rem%10;
a[j++]=a[i--];
carry=rem/10;
if(i<0&&j>length-1)
break;
}
}
else
{
if(a[i]<a[j] || count<0)
{
rem=a[i]+1;
a[i]=rem%10;
a[j++]=a[i--];
carry=rem/10;
while(carry!=0)
{
rem=a[i]+1;
a[i]=rem%10;
a[j++]=a[i--];
carry=rem/10;
if(i<0&&j>length-1)
break;
}
}
else
a[j]=a[i];
}
for(i=0;i<length;i++)
{
printf("%d",a[i]);
}
printf("\n");
}
return 0;
}