剑指 Offer 21. 调整数组顺序使奇数位于偶数前面

class Solution {
    public int[] exchange(int[] nums) {
        int i = 0, j = nums.length - 1;
        while (i < j) {
            // skip odd numbers to find an even number
            while (i < j && (nums[i] & 1) == 1) {
                i++;
            }

            // skip even numbers to find an odd number
            while (i < j && (nums[j] & 1) == 0) {
                j--;
            }

            swap(nums, i, j);
        }

        return nums;
    }

    private void swap(int[] nums, int i, int j) {
        int tmp = nums[i];
        nums[i] = nums[j];
        nums[j] = tmp;
    }
}

Reference

剑指 Offer 21. 调整数组顺序使奇数位于偶数前面