445. Add Two Numbers II(链表求和)
You are given two non-empty linked lists representing two non-negative integers. The most significant digit comes first 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.
Follow up:
What if you cannot modify the input lists? In other words, reversing the lists is not allowed.
Example:
Input: (7 -> 2 -> 4 -> 3) + (5 -> 6 -> 4) Output: 7 -> 8 -> 0 -> 7
方法一:这个题涉及到加法运算。记得设置进位,从链表尾开始进行加法运算,所以我得想办法从尾部向前运算,链表是单向,所以想到栈结构,后进先出。最后返回的是链表,
所以得设置两个指针,一个标记链表头,另一个参与运算。
时间复杂度:o(n) 空间复杂度:o(n)
苟有恒,何必三更眠五更起;最无益,莫过一日暴十日寒。