题目描述
从上往下打印出二叉树的每个节点，同层节点从左至右打印。
示例1
输入
{5,4,#,3,#,2,#,1}
返回值
[5,4,3,2,1]
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| /*
struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
TreeNode(int x) :
val(x), left(NULL), right(NULL) {
}
};*/
class Solution {
public:
vector<int> PrintFromTopToBottom(TreeNode* root) {
vector<int> result;
if(root==NULL)
return result;
result.push_back(root->val);
PrintLeftToRight(result,root);
return result;
}
void PrintLeftToRight(vector<int>&result,TreeNode* root)
{
if(root==NULL||root->left==NULL&&root->right==NULL)
return;
if(root->left)
result.push_back(root->left->val);
if(root->right)
result.push_back(root->right->val);
PrintLeftToRight(result,root->left);
PrintLeftToRight(result,root->right);
}
};
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| /*
struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
TreeNode(int x) :
val(x), left(NULL), right(NULL) {
}
};*/
class Solution {
public:
vector<int> PrintFromTopToBottom(TreeNode* root) {
vector<int> result;
if(root==NULL)
return result;
queue<TreeNode*> nodeQ;
nodeQ.push(root);
while(!nodeQ.empty())
{
TreeNode* cur = nodeQ.front();
nodeQ.pop();
result.push_back(cur->val);
if(cur->left)nodeQ.push(cur->left);
if(cur->right)nodeQ.push(cur->right);
}
return result;
}
};
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| /*
struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
TreeNode(int x) :
val(x), left(NULL), right(NULL) {
}
};*/
class Solution {
public:
vector<int> PrintFromTopToBottom(TreeNode* root) {
vector<int> result;
if(root==NULL)
return result;
queue<TreeNode*> nodeQ;
nodeQ.push(root);
int level = 0;
while(!nodeQ.empty())
{
int qS = nodeQ.size();
while(qS--)
{
TreeNode* cur = nodeQ.front();
nodeQ.pop();
result.push_back(cur->val);
if(cur->left)nodeQ.push(cur->left);
if(cur->right)nodeQ.push(cur->right);
}
level++;
}
return result;
}
};
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