```
public class Solution {
public void sortColors(int[] nums) {
int i = -1;
int j = nums.length;
for (int k = 0; k < j; k++){
if (nums[k] == 2){
swap(nums, k, --j);
k--;
}else if (nums[k] == 0){
swap(nums, ++i, k);
}
}
}
public void swap(int[] nums, int i, int j){
int tmp = nums[i];
nums[i] = nums[j];
nums[j] = tmp;
}
}
```