1、如何判断一棵树是否是完全二叉树？

int after = 1;//表示还有结点入队
bool isComplete = true;
void layerOrder(Node* root) {
    queue<Node*> Q;
    Q.push(root);
    while (!Q.empty()) {
        Node* front = Q.front();
        Q.pop();
        layer.push_back(front->v);

        if (front->lchild != NULL) {
            if (after == 0) isComplete = false;
            Q.push(front->lchild);
        }
        else {
            after = 0;//以后没有结点入队
        }

        if (front->rchild != NULL) {
            if (after == 0) isComplete = false;
            Q.push(front->rchild);
        }
        else {
            after = 0;
        }
    }
}