22 - Remove Duplicates from Sorted Array

Given a sorted array, remove the duplicates in place such that each element appear only once and return the new length.

Do not allocate extra space for another array, you must do this in place with constant memory.

For example,
Given input array A = [1,1,2],

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

solution: 两个index 一个沿着数组走，一个是不重复数字的索引，都从零开始，到数组结尾结束。

class Solution {public:    int removeDuplicates(int A[], int n) {        // Start typing your C/C++ solution below        // DO NOT write int main() function        if(A == NULL || n <= 1)            return n;                int index;        int realIndex = 0;                for(index = 0; index < n; index++)        {            if(A[ index ] != A[ realIndex ])            {                A[ ++realIndex ] = A[ index ];                            }        }                return realIndex+1;    }};