0922.cpp

class Solution {
public:
  vector<int> sortArrayByParityII(vector<int> &A) {
    int eve = 0;
    int odd = 1;
    int size = A.size();
    while (eve < size && odd < size) {
      while (eve < size && A[eve] % 2 == 0) {
        eve += 2;
      }
      while (odd < size && A[odd] % 2 == 1) {
        odd += 2;
      }
      if (eve < size && odd < size) {
        int temp = A[eve];
        A[eve] = A[odd];
        A[odd] = temp;
        eve += 2;
        odd += 2;
      }
    }
    return A;
  }
};