C＋＋判断完全二叉树

以下是C++判断完全二叉树的代码实现：

#include <iostream>
#include <vector>
#include <queue>
using namespace std;

struct TreeNode {
    int val;
    TreeNode *left;
    TreeNode *right;
    TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

bool isCompleteTree(TreeNode* root) {
    if(!root) return true;
    queue<TreeNode*> q;
    q.push(root);
    bool flag = false;
    while(!q.empty()) {
        TreeNode* cur = q.front();        q.pop();
        if(!cur) {
            flag = true;
            continue;
        }
        if(flag) return false;
        q.push(cur->left);
        q.push(cur->right);
    }
    return true;
}

TreeNode* createTree(vector<int>& values) {
    if(values.empty()) return NULL;    TreeNode* root = new TreeNode(values[0]);
    queue<TreeNode*> q;
    q.push(root);
    int i = 1;
    while(!q.empty() && i < values.size()) {
        TreeNode* cur = q.front();
        q.pop();
        if(values[i] != -1) {
            cur->left = new TreeNode(values[i]);
            q.push(cur->left);
        }
        i++;
        if(i >= values.size()) break;
        if(values[i] != -1) {
            cur->right = new TreeNode(values[i]);
            q.push(cur->right);
        }
        i++;
    }
    return root;
}

void destroyTree(TreeNode* root) {
    if(!root) return ;
    destroyTree(root->left);
    destroyTree(root->right);
    delete root;
}

int main() {
    int num;
    cin >> num;
    vector<int> values(num);
    for(unsigned int i=0;i<num;i++) cin >> values[i];
    TreeNode* root = createTree(values);
    cout << isCompleteTree(root) << endl;
    destroyTree(root);
    return 0;
}