Given an array A
of 0
s and 1
s, consider N_i
: the i-th subarray from A[0]
to A[i]
interpreted as a binary number (from most-significant-bit to least-significant-bit.)
Return a list of booleans answer
, where answer[i]
is true
if and only if N_i
is divisible by 5.
Example 1:
Input: [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: [1,1,1] Output: [false,false,false]
Example 3:
Input: [0,1,1,1,1,1] Output: [true,false,false,false,true,false]
Example 4:
Input: [1,1,1,0,1] Output: [false,false,false,false,false]
Note:
1 <= A.length <= 30000
A[i]
is 0
or 1
struct Solution;
impl Solution {
fn prefixes_div_by5(a: Vec<i32>) -> Vec<bool> {
let mut x = 0;
let n = a.len();
let mut res: Vec<bool> = vec![false; n];
for i in 0..n {
x = (x * 2 + a[i]) % 5;
res[i] = x == 0;
}
res
}
}
#[test]
fn test() {
let a = vec![0, 1, 1];
let res = vec![true, false, false];
assert_eq!(Solution::prefixes_div_by5(a), res);
let a = vec![1, 1, 1];
let res = vec![false, false, false];
assert_eq!(Solution::prefixes_div_by5(a), res);
let a = vec![0, 1, 1, 1, 1, 1];
let res = vec![true, false, false, false, true, false];
assert_eq!(Solution::prefixes_div_by5(a), res);
let a = vec![1, 1, 1, 0, 1];
let res = vec![false, false, false, false, false];
assert_eq!(Solution::prefixes_div_by5(a), res);
}