删除排列数组中的重复数字

class Solution {  
public:  
    /** 
     * @param A: a list of integers 
     * @return : return an integer 
     */  
    int removeDuplicates(vector<int> &numbers) {  
        if(numbers.empty())  
        {  
            return 0;  
        } 
          
        int a = numbers.size(),m=0;  
          
        for(int i=1;i<a;++i)  
        {  
            if(numbers[i] != numbers[m])  
            {  
                numbers[++m] = numbers[i];  
            } 
        }  
        numbers.resize(m+1);  
        return m+1;  
    }  
};