按层打印二叉树

题目描述

Code

#include <bits/stdc++.h>

using namespace std;

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;
queue<TreeNode* > Q;
if(pRoot)
Q.push(pRoot);
int num = 1;
int dept=0;
while(!Q.empty()){
int num1=0;
vector<int >vc;
for(int i=0;i<num;i++){
TreeNode* tmp=Q.front();
Q.pop();
if(tmp->left)
Q.push(tmp->left),num1++;
if(tmp->right)
Q.push(tmp->right),num1++;
vc.push_back(tmp->val);
}
ans.push_back(vc);
dept++;
num=num1;
}
return ans;
}
}f;

int main() {
TreeNode f1=TreeNode(1);
TreeNode f2=TreeNode(2);
TreeNode f3=TreeNode(3);
TreeNode f4=TreeNode(4);
f1.left=&f2;
f2.left=&f4;
f1.right=&f3;
TreeNode* root = &f1;
vector<vector<int> > c = f.Print(root);
for(int i=0;i<=2;i++){
vector<int > tmp = c[i];
for(int j=0;j<tmp.size();j++)
printf("%d ",tmp[j]);
puts("");
}
return 0;
}