LeetCode --- Remove Element

题目链接

题意：给出长度为ｎ的数组，和整数elem，　要求删除数组中存在的elem，返回最终的数组长度。

附上代码：

class Solution {
public:
    int removeElement(int A[], int n, int elem) {
        // "front" and "back" keep trace of array A from the front 
        //  and the back seperately
        // "count" holds the number of "elem" in array A
        int front = 0, back = n - 1, count = 0;
        while (true) {
            while (back >= 0 && A[back] == elem) {
                count++;
                back--;
            }
            while (front < n && A[front] != elem) front++;
            if (front > back) break;
            swap(A[front], A[back]);
            count++;
            front++, back--;
        }
        return n - count;
    }
};