题目简述:
填充它的每个next指针,注意这里并不是完美二叉树。
class Solution {
public:
Node* connect(Node* root) {
if(root == nullptr) return root;
vector<Node*> last_level;
last_level.push_back(root);
vector<Node*> now_level;
while(last_level.size() != 0) {
now_level.clear();
for(auto node:last_level) {
if(node->left != nullptr) {
now_level.push_back(node->left);
}
if(node->right != nullptr) {
now_level.push_back(node->right);
}
}
if(now_level.size() != 0) {
for(int i = 0; i < now_level.size()-1; i++) {
now_level[i]->next = now_level[i+1];
}
}
last_level.clear();
auto iter = last_level.insert(end(last_level), begin(now_level), end(now_level));
}
return root;
}
};
注意在18行加了一个now_level.size() != 0的判断语句,
不知道为什么这样会报错?望网友解答
for(int i = 0; i < -1; i++) {
cout<<now_level[i]->val; // 报错
}