Description#
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.
The most significant bit is at the head of the linked list.
Example 1:
![](https://spcdn.pages.dev/leetcode/problems/1290.Convert%20Binary%20Number%20in%20a%20Linked%20List%20to%20Integer/images/graph-1.png)
Input: head = [1,0,1]
Output: 5
Explanation: (101) in base 2 = (5) in base 10
Example 2:
Input: head = [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
.
Solutions#
Solution 1#
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| # Definition for singly-linked list.
# class ListNode:
# def __init__(self, val=0, next=None):
# self.val = val
# self.next = next
class Solution:
def getDecimalValue(self, head: ListNode) -> int:
ans = 0
while head:
ans = ans << 1 | head.val
head = head.next
return ans
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| /**
* Definition for singly-linked list.
* public class ListNode {
* int val;
* ListNode next;
* ListNode() {}
* ListNode(int val) { this.val = val; }
* ListNode(int val, ListNode next) { this.val = val; this.next = next; }
* }
*/
class Solution {
public int getDecimalValue(ListNode head) {
int ans = 0;
for (; head != null; head = head.next) {
ans = ans << 1 | head.val;
}
return ans;
}
}
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| /**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* ListNode *next;
* ListNode() : val(0), next(nullptr) {}
* ListNode(int x) : val(x), next(nullptr) {}
* ListNode(int x, ListNode *next) : val(x), next(next) {}
* };
*/
class Solution {
public:
int getDecimalValue(ListNode* head) {
int ans = 0;
for (; head; head = head->next) {
ans = ans << 1 | head->val;
}
return ans;
}
};
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| /**
* Definition for singly-linked list.
* type ListNode struct {
* Val int
* Next *ListNode
* }
*/
func getDecimalValue(head *ListNode) (ans int) {
for ; head != nil; head = head.Next {
ans = ans<<1 | head.Val
}
return
}
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| /**
* Definition for singly-linked list.
* class ListNode {
* val: number
* next: ListNode | null
* constructor(val?: number, next?: ListNode | null) {
* this.val = (val===undefined ? 0 : val)
* this.next = (next===undefined ? null : next)
* }
* }
*/
function getDecimalValue(head: ListNode | null): number {
let ans = 0;
for (; head; head = head.next) {
ans = (ans << 1) | head.val;
}
return ans;
}
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| // Definition for singly-linked list.
// #[derive(PartialEq, Eq, Clone, Debug)]
// pub struct ListNode {
// pub val: i32,
// pub next: Option<Box<ListNode>>
// }
//
// impl ListNode {
// #[inline]
// fn new(val: i32) -> Self {
// ListNode {
// next: None,
// val
// }
// }
// }
impl Solution {
pub fn get_decimal_value(head: Option<Box<ListNode>>) -> i32 {
let mut ans = 0;
let mut cur = &head;
while let Some(node) = cur {
ans = (ans << 1) | node.val;
cur = &node.next;
}
ans
}
}
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| /**
* Definition for singly-linked list.
* function ListNode(val, next) {
* this.val = (val===undefined ? 0 : val)
* this.next = (next===undefined ? null : next)
* }
*/
/**
* @param {ListNode} head
* @return {number}
*/
var getDecimalValue = function (head) {
let ans = 0;
for (; head; head = head.next) {
ans = (ans << 1) | head.val;
}
return ans;
};
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| /**
* Definition for a singly-linked list.
* class ListNode {
* public $val = 0;
* public $next = null;
* function __construct($val = 0, $next = null) {
* $this->val = $val;
* $this->next = $next;
* }
* }
*/
class Solution {
/**
* @param ListNode $head
* @return Integer
*/
function getDecimalValue($head) {
$rs = [];
while ($head != null) {
array_push($rs, $head->val);
$head = $head->next;
}
$rsStr = implode($rs);
return bindec($rsStr);
}
}
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| /**
* Definition for singly-linked list.
* struct ListNode {
* int val;
* struct ListNode *next;
* };
*/
int getDecimalValue(struct ListNode* head) {
int ans = 0;
struct ListNode* cur = head;
while (cur) {
ans = (ans << 1) | cur->val;
cur = cur->next;
}
return ans;
}
|