-
Notifications
You must be signed in to change notification settings - Fork 0
/
LC2addTwoNumbers.cpp
66 lines (63 loc) · 1.81 KB
/
LC2addTwoNumbers.cpp
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
struct ListNode {
int val;
ListNode *next;
ListNode() : val(0), next(nullptr) {}
ListNode(int x) : val(x), next(nullptr) {}
ListNode(int x, ListNode *next) : val(x), next(next) {}
};
class Solution {
public:
ListNode *addTwoNumbers(ListNode *l1, ListNode *l2) {
if (l1 == nullptr) return l2;
if (l2 == nullptr) return l1;
long len1 = getLength(l1);
long len2 = getLength(l2);
return (len1 >= len2) ? addTwoNumbersL1IsLonger(l1, l2)
: addTwoNumbersL1IsLonger(l2, l1);
}
private:
long getLength(ListNode *l) {
long i = 0;
while (l != nullptr) {
l = l->next;
i++;
}
return i;
}
ListNode *addTwoNumbersL1IsLonger(ListNode *l1, ListNode *l2) {
ListNode *a = new ListNode();
ListNode *p = a;
int overflow = 0;
while (l2 != nullptr) {
int sum = l1->val + l2->val + overflow;
p->val = sum % 10;
overflow = sum / 10;
l1 = l1->next;
l2 = l2->next;
ListNode *newL = new ListNode();
p->next = newL;
p = p->next;
}
while (l1 != nullptr) {
int sum = l1->val + overflow;
p->val = sum % 10;
overflow = sum / 10;
l1 = l1->next;
ListNode *newL = new ListNode();
p->next = newL;
p = p->next;
}
p->val = overflow;
checkAndRemoveTailZero(a);
return a;
}
void checkAndRemoveTailZero(ListNode *l) {
ListNode *p = l;
if (p->next == nullptr) return;
while (p->next->next != nullptr) p = p->next;
if (p->next->val == 0) {
delete p->next;
p->next = nullptr;
}
}
};