Leetcode: Remove Element

http://oj.leetcode.com/problems/remove-element/

class Solution {
public:
    int removeElement(int A[], int n, int elem) {
        if(n==0) return 0;
        int start=0, end=n-1;
        while(start<end){
            while(start<end&&A[start]!=elem) start++;
            while(start<end&&A[end]==elem) end--;
            swap(A[start],A[end]);
        }
        if(A[start]==elem) return start;
        else return start+1;
    }
};