922. Sort Array By Parity II

Given an array A of non-negative integers, half of the integers in A are odd, and half of the integers are even.

Sort the array so that whenever A[i] is odd, i is odd; and whenever A[i] is even, i is even.

You may return any answer array that satisfies this condition.

 

Example 1:

Input: [4,2,5,7]
Output: [4,5,2,7]
Explanation: [4,7,2,5], [2,5,4,7], [2,7,4,5] would also have been accepted.

 

Note:

  1. 2 <= A.length <= 20000
  2. A.length % 2 == 0
  3. 0 <= A[i] <= 1000

 

Rust Solution

struct Solution;

impl Solution {
    fn sort_array_by_parity_ii(mut a: Vec<i32>) -> Vec<i32> {
        let n = a.len();
        let mut i: usize = 0;
        let mut j: usize = 1;
        while i < n && j < n {
            while i < n && a[i] % 2 == 0 {
                i += 2;
            }
            while j < n && a[j] % 2 == 1 {
                j += 2;
            }
            if i < n && j < n {
                a.swap(i, j);
            }
        }
        a
    }
}

#[test]
fn test() {
    let a = vec![4, 2, 5, 7];
    let b = vec![4, 5, 2, 7];

    assert_eq!(Solution::sort_array_by_parity_ii(a), b);
}

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