Code :
#include <stdio.h>
#include <stdlib.h>
typedef struct Node {
unsigned char c;
struct Node \*next;
```
```
}Node;
```
```
typedef Node \*slist;
```
```
slist reverse(slist);
Node *makeNode(unsigned char);
/*
\*/
```
```
slist Sum(slist left, slist right) {
```
```
if(!left || !right) {
return left ? left : right;
}
```
```
left = reverse(left);
right = reverse(right);
unsigned char carry = left->c + right->c;
slist ret = makeNode(carry % 10);
carry /= 10;
```
```
Node \*p = left->next;
Node *q = right->next;
Node \*r = ret;
```
```
while(p || q) {
```
```
carry += (p? p->c : 0) + (q ? q->c : 0);
```
```
r->next = makeNode(carry % 10);
carry /= 10;
r = r->next;
p = p ? p->next : NULL;
q = q ? q->next : NULL;
}
```
```
if(carry)
r->next = makeNode(1);
reverse(left);
reverse(right);
```
```
return reverse(ret);
```
```
}
```
```
/\*
utilities
\*/
```
```
slist reverse(slist s) {
```
```
if(s->next == NULL)
return s;
Node *ret = reverse(s->next);
s->next->next = s;
s->next = NULL;
```
```
return ret;
}
Node *makeNode(unsigned char c) {
Node * tmp = calloc(sizeof(Node), 1);
tmp->c = c;
return tmp;
}
void print(slist s) {
if(s == NULL) {
printf("\\n");
return;
}
printf("%c”, s->c + ‘0’);
print(s->next);
}
```
```
slist listFromString(const unsigned char \*s) {
```
```
if(!s || !\*s) return NULL;
```
```
slist ret = makeNode(\*s++ - '0');
```
```
Node \*tmp = ret;
```
```
unsigned char c;
```
```
while((c = \*s++)) {
tmp->next = makeNode(c - ‘0’);
tmp = tmp->next;
}
return ret;
}
```
```
int main()
{
slist left = listFromString("99");
slist right = listFromString(“233823”);
slist sum = Sum(left, right);
print(sum);
return 0;
}