Sort array by parity ii

Array Two Pointers Sorting

71.2% acceptance

Feb 25, 2026

2809

104

Given an array of integers nums, half of the integers in nums are odd, and the other half are even. Sort the array so that whenever nums[i] is odd, i is odd, and whenever nums[i] is even, i is even. Return any answer array that satisfies this condition.

Solution

Rust

Time O(n²)

Space O(1)

LeetCode

solution.rs

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