High-precision addition and subtraction. Addition is OK, subtraction took a lot of time.

Addition:

#include <stdio.h>
#include <string.h>
int a[1000]={0},b[1000]={0};
int main ()
{
Char *s1;
int l1=0,l2=0,l,i;
Freopen ("Hp+.in", "R", stdin);
Freopen ("Hp+.out", "w", stdout);
scanf ("%s", S1);
L1=strlen (S1);
for (i=0;i<=l1-1;i++)
{
a[l1-1-i]=s1[i]-' 0 ';
}
scanf ("%s", S1);
L2=strlen (S1);
for (i=0;i<=l2-1;i++)
{
b[l2-1-i]=s1[i]-' 0 ';
}
if (L1&GT;L2)
L=L1;
Else
L=L2;
for (i=0;i<=l-1;i++)
{
A[i]=a[i]+b[i];
if (a[i]>=10)
{
a[i+1]=a[i+1]+1;
a[i]=a[i]-10;
}
}
if (a[l]!=0)
l++;
for (i=l-1;i>=0;i--)
printf ("%d", a[i]);
return 0;
}

Subtraction:

#include <stdio.h> #include <string.h> int a[1000]={0},b[1000]={0},c[1000]={0};  int main () {char *s1;  int l1=0,l2=0,l,i,x;  Freopen ("Hp-.in", "R", stdin);  Freopen ("Hp-.out", "w", stdout);  scanf ("%s", S1);  L1=strlen (S1);  for (i=0;i<=l1-1;i++) {a[l1-1-i]=s1[i]-' 0 ';  } scanf ("%s", S1);  L2=strlen (S1);  for (i=0;i<=l2-1;i++) {b[l2-1-i]=s1[i]-' 0 ';  } if (L1>L2) l=l1;  else L=l2; for (i=0;i<=l-1;i++) {

  if (A[i]<b[i])   {   c[i]=a[i]+10-b[i];    c[i+1]=a[i+1 ]-1;   }   else       c[i]=a[i]-b[i];    }     for (i=l-1;i>=0;i++)     {     if (A[i] <b[i])      {        x=1;    }   else & nbsp;   break;  }     if (x==1)     {     printf ("-");      for (i=0;i<=l-1;i++)  {

if (B[i]<a[i]) {c[i]=b[i]+10-a[i];   C[i+1]=b[i+1]-1;     } else c[i]=b[i]-a[i];      }} for (i=l-1;i>=0;i--) {if (c[i]==0) l--;   else break;  } for (i=l-1;i>=0;i--) printf ("%d", c[i]);        return 0; }

High-precision addition and subtraction. Addition is OK, subtraction took a lot of time.