[LeetCode] Remove Element

Thought:
Iterate from the end of the array, if we find a match we exchange the current value and the len-1 index value, and then update the len.

Code:
public class Solution {
    public int removeElement(int[] A, int elem) {
        int len = A.length;
        for(int i = A.length - 1; i >= 0; i--){
            if(A[i] == elem){
                A[i] = A[len - 1];
                len--;
            }
        }
        return len;
    }
}