按之字形順序列印二叉樹 c++實現
題目描述
請實現一個函式按照之字形列印二叉樹，即第一行按照從左到右的順序列印，第二層按照從右至左的順序列印，第三行按照從左到右的順序列印，其他行以此類推。/*
struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
TreeNode(int x) :
val(x), left(NULL), right(NULL) {
}
};
*/
class Solution {
public:
vector<vector<int> > Print(TreeNode* pRoot) {
vector<vector<int> > result;
vector<int> item;
if(pRoot==NULL) return result;
queue<pair<TreeNode*,int> > Q;//奇數層輸出 ，從左到右
Q.push(make_pair(pRoot,1));
int is_put=0;
int new_deep=0;
while(!Q.empty())
{
int deep=Q.front().second;
TreeNode* node=Q.front().first;
if(item.size()==0)
{
item.push_back(node->val);
new_deep=deep;
}else
{
if(new_deep!=deep)
{
if(new_deep%2==0)
{
jiaohuan(item);
}
result.push_back(item);
item.clear();
item.push_back(node->val);
new_deep=deep;
}else
{
item.push_back(node->val);
}
}
Q.pop();
if(node->left)
{
Q.push(make_pair(node->left,deep+1));
}
if(node->right)
{
Q.push(make_pair(node->right,deep+1));
}
}
if(item.size()!=0)
{
if(new_deep%2==0)
{
jiaohuan(item);
}
result.push_back(item);
}
return result;
}
private:
void jiaohuan(vector<int>& item)
{
int i=0;
int j=item.size()-1;
while(i<j)
{
int T=item[i];
item[i]=item[j];
item[j]=T;
i++;j--;
}
}
};