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// 445. Add Two Numbers II
#include "leetcode.h"
/*
* given two non-empty linked lists representing two non-negative integers. the
* most significant digit comes first and each of their nodes contains a single
* digit. add the two numbers and return the same as a linked list. you may
* assume the two numbers do not contain any leading zero, except the number 0
* itself.
*/
class Solution {
ListNode *append(int val, ListNode *head) {
ListNode *tmp = new ListNode(val);
tmp->next = head;
return tmp;
}
public:
ListNode *addTwoNumbers(ListNode *l1, ListNode *l2) {
int n1 = 0, n2 = 0, carry = 0;
ListNode *curr1 = l1, *curr2 = l2, *ans = NULL;
while (curr1)
curr1 = curr1->next, n1++;
while (curr2)
curr2 = curr2->next, n2++;
curr1 = l1, curr2 = l2;
while (n1 && n2) {
int sum = 0;
if (n1 >= n2) {
sum += curr1->val;
curr1 = curr1->next;
n1--;
}
if (n2 > n1) {
sum += curr2->val;
curr2 = curr2->next;
n2--;
}
ans = append(sum, ans);
}
curr1 = ans;
ans = NULL;
while (curr1) {
curr1->val += carry;
carry = curr1->val / 10;
ans = append(curr1->val % 10, ans);
curr2 = curr1;
curr1 = curr1->next;
delete curr2;
}
if (carry)
ans = append(1, ans);
return ans;
}
};
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