Remove Duplicates from Sorted Array II

自己搞定

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].

C++

class Solution {
public:
    int removeDuplicates(int A[], int n) {
        if(n<3) return n;
        
        int index = 1, count = 1;
        for(int i=1;i<n;i++){
            if(A[i]==A[index-1] && count<2){
                A[index++] = A[i];
                count += 1;
            }
            if(A[i]!=A[index-1]){
                A[index++] = A[i];
                count = 1;
            }
        }
        
        return index;
        
    }
};

summary:

数组可以in-place的替换，这个一定要掌握。 相当于前面是一个新数组，后面是一个数组。