leetcode-Binary Tree Level Order Traversal(2014.1.22)
2014-04-15 20:07
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//记载每一行有多少个节点,采用队列结构
/**
* Definition for binary tree
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
vector<vector<int> > levelOrder(TreeNode *root) {
vector<vector<int>> path;
vector<int> vec;
queue<TreeNode*> stk;
TreeNode* cur=NULL;
int num1=1,num2=0;
if(root==NULL) return path;
stk.push(root);
while(stk.empty()!=true)
{
vec.clear();
for(int j=0;j<num1;j++){
cur=stk.front();
vec.push_back(cur->val);
stk.pop();
if(cur->left!=NULL){
num2++;
stk.push(cur->left);
cur->left=NULL;
}
if(cur->right!=NULL){
num2++;
stk.push(cur->right);
cur->right=NULL;
}
}
num1=num2;
num2=0;
path.push_back(vec);
}
return path;
}
};
/**
* Definition for binary tree
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
vector<vector<int> > levelOrder(TreeNode *root) {
vector<vector<int>> path;
vector<int> vec;
queue<TreeNode*> stk;
TreeNode* cur=NULL;
int num1=1,num2=0;
if(root==NULL) return path;
stk.push(root);
while(stk.empty()!=true)
{
vec.clear();
for(int j=0;j<num1;j++){
cur=stk.front();
vec.push_back(cur->val);
stk.pop();
if(cur->left!=NULL){
num2++;
stk.push(cur->left);
cur->left=NULL;
}
if(cur->right!=NULL){
num2++;
stk.push(cur->right);
cur->right=NULL;
}
}
num1=num2;
num2=0;
path.push_back(vec);
}
return path;
}
};