Binary prefix divisible by 5

Array Bit Manipulation

53.5% acceptance

Feb 25, 2026

1101

230

You are given a binary array nums (0-indexed). We define xi as the number whose binary representation is the subarray nums[0..i] (from most-significant-bit to least-significant-bit). For example, if nums = [1,0,1], then x0 = 1, x1 = 2, and x2 = 5. Return an array of booleans answer where answer[i] is true if xi is divisible by 5.

Solution

Rust

Time O(n)

Space O(1)

LeetCode

solution.rs

impl Solution {
  pub fn prefixes_div_by5(nums: Vec<i32>) -> Vec<bool> {
    let mut cur = 0;
    nums.iter().map(|&b| { cur = (cur * 2 + b) % 5; cur == 0 }).collect()
  }
}