80. Remove Duplicates from Sorted Array II

就是比之前的多一个flag记录有没有重复过一次

    public int removeDuplicates(int[] nums) {
        if(nums == null || nums.length == 0) {
            return 0;
        }
        boolean flag = false;
        int index = 1;
        for(int i = 1; i < nums.length; i++) {
            if(nums[i-1] == nums[i]) {
                if(flag == false) {
                    flag = true;
                    nums[index++] = nums[i];
                }
            } else {
                nums[index++] = nums[i];
                flag = false;
            }
        }
        return index;
    }