Convert binary number in a linked list to integer

Linked List Math

82.3% acceptance

Feb 25, 2026

4668

177

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.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn get_decimal_value(mut head: Option<Box<ListNode>>) -> i32 {
    let mut result = 0;
    while let Some(node) = head {
      result = result * 2 + node.val;
      head = node.next;
    }
    result
  }
}