Add Two Numbers
Medium · Linked List
Each of two linked lists represents a non-negative integer with its digits stored in reverse order, one digit per node. Add the two numbers and return the sum as a new linked list, also with digits in reverse order. Assume neither input list has a leading zero unless the number itself is zero.
Examples
Input: l1 = [2,4,3], l2 = [5,6,4]
Output: [7,0,8]
Why: 342 plus 465 equals 807, and 807 written with least significant digit first is [7,0,8].Input: l1 = [0], l2 = [0]
Output: [0]
Why: 0 plus 0 is 0.Input: l1 = [9,9,9,9], l2 = [9,9]
Output: [8,9,0,0,1]
Why: 9999 plus 99 equals 10098, and reversed digit order gives [8,9,0,0,1].Constraints
1 <= number of nodes in each list <= 100, 0 <= node value <= 9, the lists do not contain leading zeros unless the number itself is 0
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This statement is written for CodeSpeek. The problem is part of the NeetCode 150 list; Watch NeetCode's explanation of Add Two Numbers. Reference solutions from the NeetCode repository (MIT) are used to verify our tests.