1290. Convert Binary Number in a Linked List to Integer*
https://leetcode.com/problems/convert-binary-number-in-a-linked-list-to-integer/
题目描述
Given head which is a reference node to a singly-linked list. The value of each node in the linked list is either 0 or 1. The linked list holds the binary representation of a number.
Return the decimal value of the number in the linked list.
Example 1:
Input: head = [1,0,1]
Output: 5
Explanation: (101) in base 2 = (5) in base 10
Example 2:
Input: head = [0]
Output: 0
Example 3:
Input: head = [1]
Output: 1
Example 4:
Input: head = [1,0,0,1,0,0,1,1,1,0,0,0,0,0,0]
Output: 18880
Example 5:
Input: head = [0,0]
Output: 0
Constraints:
- The Linked List is not empty.
- Number of nodes will not exceed 30.
- Each node’s value is either 0 or 1.
C++ 实现 1
代码中 res << 1 表示 res * 2.
class Solution {
public:
int getDecimalValue(ListNode* head) {
if (!head) return 0;
auto p = head;
int res = 0;
while (p) {
res = (res << 1) + p->val;
p = p->next;
}
return res;
}
};
