LeetCode 1290. Convert Binary Number in a Linked List to Integer

想法

這一題我們先用一變數來存放之前的值，每向前一位，就將原值向左移一位（乘以 2），並且加上新的值。

Solution

C

int getDecimalValue(struct ListNode* head) {
    long long result = 0;
    while (head) {
        result <<= 1;
        result += head->val;
        head = head->next;
    }
    return result;
}

CPP

class Solution {
public:
    int getDecimalValue(ListNode* head) {
        long long result = 0;
        while (head) {
            result <<= 1;
            result += head->val;
            head = head->next;
        }
        return result;
    }
};

JAVA

class Solution {
    public int getDecimalValue(ListNode head) {
        var result = 0;
        
        while (head != null) {
            result <<= 1;
            result += head.val;
            head = head.next;
        }
        return result;
    }
}

JAVASCRIPT

function getDecimalValue(head) {
    let result = 0;
    while (head) {
        result <<= 1;
        result += head.val;
        head = head.next;
    }
    return result;
}

PHP

class Solution {

/**
 * @param ListNode $head
 * @return Integer
 */
function getDecimalValue($head) {
    $result = 0;
    
    while ($head != null) {
        $result <<= 1;
        $result += $head->val;
        $head = $head->next;
    }
    return $result;
}
}

PYTHON

class Solution:
    def getDecimalValue(self, head: ListNode) -> int:
        result = 0
        
        while head != None:
            result <<= 1
            result += head.val
            head = head.next
        
        return result

TYPESCRIPT

function getDecimalValue(head: ListNode | null): number {
    let result = 0;
    while (head !== null) {
        result <<= 1;
        result += head.val;
        head = head.next;
    }
    return result;
}