public void sortColors(int[] nums) {
        int count1 = 0, count2 = 0;
        for(int i: nums){
            if(i == 1) count1++;
            else if(i == 2) count2++;
        }
        int count0 = nums.length-count1-count2;
        
        int i = 0;
        while(i < count0){
            nums[i] = 0;
            i++;
        }
        i = 0;
        while(i < count1){
            nums[i+count0] = 1;
            i++;
        }
        i = 0;
        while(i < count2){
            nums[i+count0+count1] = 2;
            i++;
        }
    }