游戏大赛决赛，两组选手分别按得分从小到大排好队，需要合并成一个有序排行榜。A组：A = {12, 35, 67, 89}，B组：B = {20, 45, 55, 78}。归并合并函数的核心循环代码如下：

int i = 0, j = 0;
vector<int> result;

while (i < A.size() && j < B.size()) {
  if (___________________) {
    result.push_back(A[i++]);
  } else {
    result.push_back(B[j++]);
  }
}

while (i < A.size()) {
  result.push_back(A[i++]);
}

while (j < B.size()) {
  result.push_back(B[j++]);
}