binary-prefix-divisible-by-5

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1018. Binary Prefix Divisible By 5 (Easy)

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.

 

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]

Example 3:

Input: nums = [0,1,1,1,1,1]
Output: [true,false,false,false,true,false]

Example 4:

Input: nums = [1,1,1,0,1]
Output: [false,false,false,false,false]

 

Constraints:

• 1 <= nums.length <= 105
• nums[i] is 0 or 1.

Related Topics

[Array]

Hints

Hint 1

If X is the first i digits of the array as a binary number, then 2X + A[i] is the first i+1 digits.