题目描述:给定一个 N 叉树,返回其节点值的前序遍历。
代码:
/*
// Definition for a Node.
class Node {
public:
int val;
vector<Node*> children;
Node() {}
Node(int _val) {
val = _val;
}
Node(int _val, vector<Node*> _children) {
val = _val;
children = _children;
}
};
*/
class Solution {
public:
vector<int> preorder(Node* root) {
vector<int>res;
if(!root)
return res;
stack<Node*>stk;
stk.push(root);
while(!stk.empty()){
Node*tmp=stk.top();
stk.pop();
res.push_back(tmp->val);
for(int i=tmp->children.size()-1;i>=0;--i){
stk.push(tmp->children[i]);
}
}
return res;
}
};