示例：
​
输入：[4,2,5,7]
输出：[4,5,2,7]
解释：[4,7,2,5]，[2,5,4,7]，[2,7,4,5] 也会被接受。
​
​
提示：
​
2 <= A.length <= 20000
A.length % 2 == 0
0 <= A[i] <= 1000

class Solution {
public:
    vector<int> sortArrayByParityII(vector<int>& A) {
        vector<int> res(A.size(),0);
        int s1=0,s2=1;
        for(int i=0;i<A.size();i++)
        {
            if(A[i]&1)
            {
                res[s2]=A[i];
                s2+=2;
            }
            else
            {
                res[s1]=A[i];
                s1+=2;
            }
        }
        return res;
    }
};