【LeetCode027】Remove Element

class Solution {
public:
    int removeElement(vector<int>& nums, int val) {
        int len = nums.size();
        if(len == 0)
            return 0;
        int new_len = 0;
        for(int old_len = 0; old_len < len; ++old_len){
            if(nums[old_len] != val)
                nums[new_len++] = nums[old_len]; //此处old_len不能再自增了
        }
        return new_len;
    }
};