link: https://leetcode.com/problems/add-two-numbers/description/
> You are given two non-empty linked lists representing two non-negative integers. The digits are stored in reverse order and each of their nodes contain a single digit. Add the two numbers and return it as a linked list.
> You may assume the two numbers do not contain any leading zero, except the number 0 itself.
Example:
```
Input: (2 -> 4 -> 3) + (5 -> 6 -> 4)
Output: 7 -> 0 -> 8
Explanation: 342 + 465 = 807.
```
# JavaScript
> 小于32位的数字
```js
/**
* Definition for singly-linked list.
* function ListNode(val) {
* this.val = val;
* this.next = null;
* }
*/
/**
* @param {ListNode} l1
* @param {ListNode} l2
* @return {ListNode}
*/
var addTwoNumbers = function(l1, l2) {
let arr1 = []
let arr2 = []
do {
arr1.push(l1.val)
l1 = l1.next
} while (l1 !== null)
do {
arr2.push(l2.val)
l2 = l2.next
} while (l2 !== null)
return String.prototype.split.call(parseInt(arr1.reverse().join('')) + parseInt(arr2.reverse().join('')), '').reverse().map( e => parseInt(e))
};
```
> 如果是BigDecimal
>[info] runtime: 209 ms
```js
/**
* Definition for singly-linked list.
* function ListNode(val) {
* this.val = val;
* this.next = null;
* }
*/
/**
* @param {ListNode} l1
* @param {ListNode} l2
* @return {ListNode}
*/
var addTwoNumbers = function(l1, l2) {
let a = []
let b = []
do {
a.push(l1.val)
l1 = l1.next
} while (l1 !== null)
do {
b.push(l2.val)
l2 = l2.next
} while (l2 !== null)
let figure = 0
let arr = []
let maxLen = a.length > b.length ? a.length : b.length
let minLen = a.length < b.length ? a.length : b.length
for (let i = 0; i < maxLen; i++) {
if (i < minLen) {
let sum = a[i] + b[i] + figure
if (sum >= 10) {
figure = 1
} else {
figure = 0
}
arr.push(sum % 10)
} else {
if (a.length > b.length) {
sum = a[i] + figure
if (sum >= 10) {
figure = 1
} else {
figure = 0
}
arr.push(sum % 10)
} else {
sum = b[i] + figure
if (sum >= 10) {
figure = 1
} else {
figure = 0
}
arr.push(sum % 10)
}
}
}
if (figure === 1) {
arr.push(figure)
}
return arr
};
```
>[info] runtime: 182 ms
```js
var addTwoNumbers = function(l1, l2) {
var nextNode = new ListNode(0);
var head = nextNode;
var carryover = 0;
while(true){
if(l1 != null ){
nextNode.val += l1.val;
l1 = l1.next;
}
if(l2 != null){
nextNode.val += l2.val;
l2 = l2.next;
}
if(nextNode.val > 9){
var r = nextNode.val % 10;
carryover = (nextNode.val - r) / 10;
nextNode.val = r;
}
if(carryover == 0 && l1 == null && l2 == null){
return head;
}
nextNode.next = new ListNode(carryover);
nextNode = nextNode.next;
carryover = 0;
}
return head;
};
```
>[info] runtime: 212 ms
```js
var addTwoNumbers = function(l1, l2) {
var lw = [];
var tmp, dtmp = 0;
function add(l1v, l2v){
l1v = l1v || {val : 0};
l2v = l2v || {val : 0};
tmp = l1v.val + l2v.val + dtmp;
dtmp = tmp % 10;
lw.push(dtmp);
if (tmp === dtmp){
dtmp = 0;
}else{
dtmp = 1;
}
if(l1v.next || l2v.next || dtmp)
add(l1v.next, l2v.next)
}
add(l1, l2)
return lw;
};
```
>[info] runtime: 185 ms
```js
var addTwoNumbers = function(l1, l2) {
var head, current, list1, list2;
var carry = 0, sum = 0, x = 0, y = 0;
setup();
while (list1 != null || list2 != null) {
addSumsToNode();
moveToNextNode();
}
addNewNodeIfCarryExists();
return head.next;
function setup() {
head = new ListNode(0);
current = head;
list1 = l1 || new ListNode(0);
list2 = l2 || new ListNode(0);
}
function addSumsToNode() {
x = (list1 != null) ? list1.val : 0;
y = (list2 != null) ? list2.val : 0;
sum = carry + x + y;
carry = (sum > 9) ? 1 : 0;
current.next = new ListNode(sum % 10);
}
function moveToNextNode() {
current = current.next;
list1 = (list1 != null) ? list1.next : null;
list2 = (list2 != null) ? list2.next : null;
}
function addNewNodeIfCarryExists() {
if (carry > 0) {
current.next = new ListNode(carry);
}
}
};
```
