剑指offer | 训练题59：把二叉树打印成多行

题目描述

思路

//思路：BFS
/*
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> > ans;
if(pRoot == NULL) return ans;
queue<TreeNode*> q;
q.push(pRoot);
while(!q.empty()){
int size = q.size();//读取每一层的元素的数量
vector<int> levelelem;
while(size--){
TreeNode* t = q.front();
q.pop();
levelelem.push_back(t->val);
if(t->left != NULL) q.push(t->left);
if(t->right != NULL) q.push(t->right);
}
ans.push_back(levelelem);
}
return ans;
}

};