1class Solution {2    public void sortColors(int[] nums) {3        int low = 0, i = 0, high = nums.length - 1;4        while (i <= high) {5            if (nums[i] == 0) {6                swap(nums, i, low);7                low++; i++;8            } else if (nums[i] == 2) {9                swap(nums, i, high);10                high--;11            } else i++;12        }13    }14    private void swap(int[] nums, int a, int b) {15        int temp = nums[a];16        nums[a] = nums[b];17        nums[b] = temp;18    }19}