/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode* addTwoNumbers(ListNode* l1, ListNode* l2) {
ListNode *p1,*p2,*p3,*res;
p1 = l1;
p2 = l2;
res = new ListNode(0);
p3 = res;
for( ; (p1!=NULL)&&(p2!=NULL); p1 = p1->next, p2 = p2->next){
int k = p2->val + p1->val + p3->val;
if(k >= 10){
p3->val = k - 10;
p3->next = new ListNode(1);
p3 = p3->next;
}
else{
p3->val = k;
if((p2->next != NULL) && (p1->next != NULL)){
p3->next = new ListNode(0);
p3 = p3->next;
}
else if((p2->next == NULL)&&(p1->next == NULL)){
p3->next = NULL;
}
else{
p3->next = new ListNode(0);
p3 = p3->next;
}
}
}
int temp;
if((p1==NULL)&&(p2==NULL)){
return res;
}
else if(p1 != NULL){
for(; p1 != NULL; p1 = p1->next){
temp = p1->val + p3->val;
if(temp >= 10){
p3->val = temp - 10;
p3->next = new ListNode(1);
p3 = p3->next;
}
else{
if(p1->next == NULL){
p3->val = temp;
p3->next = NULL;
break;
}
else{
p3->val = temp;
p3->next = new ListNode(0);
p3 = p3->next;
}
}
}
}
else if(p2 != NULL){
for(; p2 != NULL; p2 = p2->next){
temp = p2->val + p3->val;
if(temp >= 10){
p3->val = temp - 10;
p3->next = new ListNode(1);
p3 = p3->next;
}
else{
if(p2->next == NULL){
p3->val = temp;
p3->next = NULL;
break;
}
else{
p3->val = temp;
p3->next = new ListNode(0);
p3 = p3->next;
}
}
}
}
return res;
}
};
高阶版本
/**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode(int x) : val(x), next(NULL) {}
* };
*/
class Solution {
public:
ListNode *addTwoNumbers(ListNode *l1, ListNode *l2) {
static const int R = 10;
ListNode *p1, *p2, *p3;
ListNode *h3, *t3;
p1 = l1;
p2 = l2;
h3 = t3 = NULL;
while (p1 != NULL && p2 != NULL) {
p3 = new ListNode(p1->val + p2->val);
if (t3 == NULL) {
h3 = t3 = p3;
} else {
t3->next = p3;
t3 = p3;
}
p1 = p1->next;
p2 = p2->next;
}
while (p1 != NULL) {
t3->next = new ListNode(p1->val);
t3 = t3->next;
p1 = p1->next;
}
while (p2 != NULL) {
t3->next = new ListNode(p2->val);
t3 = t3->next;
p2 = p2->next;
}
p3 = h3;
while (p3->next != NULL) {
p3->next->val += p3->val / R;
p3->val %= R;
p3 = p3->next;
}
while (p3->next == NULL && p3->val >= R) {
p3->next = new ListNode(p3->val / R);
p3->val %= R;
p3 = p3->next;
}
return h3;
}
};
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