Description (leetcode)

You are given a binary array nums (0-indexed).

We define x_i 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 x_0 = 1, x_1 = 2, and x_2 = 5.

Return an array of booleans answer where answer[i] is true if x_i is divisible by 5.

Example 1:

Input: nums = [0,1,1]

Output: [true,false,false]

Explanation: The input numbers in binary are 0, 01, 011; which are 0, 1, and 3 in base-10.

Only the first number is divisible by 5, so answer[0] is true.

Example 2:

Input: nums = [1,1,1]

Output: [false,false,false]

Constraints:

  • 1 <= nums.length <= 10^5
  • nums[i] is either 0 or 1.

submission

impl Solution {
    pub fn prefixes_div_by5(nums: Vec<i32>) -> Vec<bool> {
        nums.into_iter()
            .scan(0, |m, v| {
                *m = (*m * 2 + v) % 5;
                Some(*m == 0)
            })
            .collect()
    }
}