leetcode -- Remove Duplicates from Sorted Array II

Follow up for "Remove Duplicates":
What if duplicates are allowed at most twice?

For example,
Given sorted array A = [1,1,1,2,2,3],

Your function should return length = 5, and A is now [1,1,2,2,3].

[解题思路]

双指针问题，还是使用count来保存结果数组的大小

与Remove Duplicates from Sorted Array唯一区别在添加start, end标识duplicates区间

如果当前区间中元素个数小于3，依次复制，如果≥3，则停止复制

public int removeDuplicates(int[] A) {
        int len = A.length;
        if(len == 0){
            return len;
        }
        
        int start = 0, end = 0;
        int count = 1;
        for(int i = 1; i < len; i++){
            if(A[i] == A[i - 1]){
                end ++;
                if(end - start < 2){
                    A[count ++] = A[i];
                }
                continue;
            } else {
                A[count ++] = A[i];
                start = i;
                end = i;
            }
        }
        return count;
    }