addTwoNumbers.js

/*
 * @Author: Z1hgq
 * @Date: 2019-09-16 14:13:15
 * @LastEditTime: 2019-09-17 14:16:55
 */
/**
 * Definition for singly-linked list.
 * function ListNode(val) {
 *     this.val = val;
 *     this.next = null;
 * }
 */
/**
 * @param {ListNode} l1
 * @param {ListNode} l2
 * @return {ListNode}
 */
const addTwoNumbers = function (l1, l2) {
  // let arrl1 = [];
  // let arrl2 = [];
  // while(l1){
  //     arrl1.push(l1.val);
  //     l1 = l1.next;
  // }
  // while(l2){
  //     arrl2.push(l2.val);
  //     l2 = l2.next;
  // }
  // l1 = null;
  // l2 = null;
  // arrl1 = arrl1.reverse();
  // arrl2 = arrl2.reverse();
  // let strl1 = '';
  // let strl2 = '';
  // for(let num of arrl1){
  //     strl1 += num;
  // }
  // for(let num of arrl2){
  //     strl2 += num;
  // }
  // arrl1 = null;
  // arrl2 = null;
  let strl1 = '';
  let strl2 = '';
  while (l1) {
    strl1 += l1.val;
    l1 = l1.next;
  }
  while (l2) {
    strl2 += l2.val;
    l2 = l2.next;
  }
  strl1 = strl1.split('').reverse().join('');
  strl2 = strl2.split('').reverse().join('');
  // 注意int有最大安全范围，超过这个范围的运算应使用BigInt，BigInt不受安全范围限制
  const res = (BigInt(strl1) + BigInt(strl2)).toString();
  strl1 = null;
  strl2 = null;
  const resNode = {
    val: res[res.length - 1],
    next: null,
  };
    // 构造链表
  for (let i = res.length - 2; i >= 0; i--) {
    let node = {
      val: res[i],
      next: null
    };
    let currentNode = resNode;
    while (currentNode.next) {
      currentNode = currentNode.next;
    }
    currentNode.next = node;
    node = null;
  }
  return resNode;
};

const l1 = {
  val: '1',
  next: {
    val: '2',
    next: {
      val: '3',
      next: null
    }
  }
};
const l2 = {
  val: '1',
  next: {
    val: '2',
    next: {
      val: '3',
      next: null
    }
  }
};
console.log(addTwoNumbers(l1, l2));