Sort-Array-By-Parity.cpp

/* 遍历整个数组，将所有偶数和奇数元素分别取出成为单独的数组，然后再进行拼接即可 */
/* 测试用例：nums = {2,1,4,3} */
/* 时间复杂度：O(N)，空间复杂度：O(N) */

#include <vector>

using namespace std;

class Solution
{
  public:
    vector<int> sortArrayByParity(vector<int> &nums)
    {
        vector<int> odds, evens, ans;
        /* odds = {1, 3} evens = {2, 4} */
        for (auto &num : nums)
            if (num & 1)
                odds.push_back(num);
            else
                evens.push_back(num);
        for (auto &num : evens)
            ans.push_back(num); // ans = {2, 4}
        for (auto &num : odds)
            ans.push_back(num); // ans = {2, 4, 1, 3}
        return ans;
    };
};