20170514_建立二叉树+前序遍历+层序遍历+栈+队列

20170514_建立二叉树+前序遍历+层序遍历+栈+队列

//102. Binary Tree Level Order Traversal /** * Definition for a binary tree node. * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */#include<iostream>#include<vector>#include<queue>#include<algorithm>using namespace std;const int SIZE=1000;struct TreeNode{int val;TreeNode *left;TreeNode *right;TreeNode(int x):val(x),left(NULL),right(NULL) {}};//建立二叉树void CreatBiTree(TreeNode * &root){int ch;cin>>ch;getchar();if(ch == -1)root=NULL;else{root=new TreeNode(ch);CreatBiTree(root->left);CreatBiTree(root->right);}}//前序遍历二叉树（使用的是栈stack）void PreOrder(TreeNode *root){TreeNode *s[SIZE];int top=-1;while(root != NULL || top != -1){while(root != NULL){cout<<root->val<<" ";s[++top]=root;root=root->left;}if(top != -1){root=s[top--];root=root->right;}}}//中序遍历二叉树（使用的是队列queue）void LevelOrder(TreeNode *root){TreeNode *Q[SIZE];int front=0;int rear=0;if(root==NULL)return;Q[++rear]=root;while(front != rear){//auto q=Q[++front];TreeNode *q=Q[++front];cout<<q->val<<" ";if(q->left != NULL)Q[++rear]=q->left;if(q->right != NULL)Q[++rear]=q->right;}}//层序遍历class Solution{public:    vector<vector<int>> levelOrder(TreeNode *root)//二维数组{vector<vector<int>> result;if(root==NULL)return result;queue<TreeNode *> q;q.push(root);while(!q.empty()){int num=q.size();vector<int> ivec;for(int i=0;i<num;++i){TreeNode *top=q.front();ivec.push_back(top->val);q.pop();if(top->left != NULL)q.push(top->left);if(top->right != NULL)q.push(top->right);}result.push_back(ivec);}//输出for(auto &cow:result){cout<<"[";auto beg=cow.begin();for(;beg!=--cow.end();++beg)cout<<*beg<<",";cout<<*beg<<"]";cout<<",";}return result;}};int main(){TreeNode *root;cout<<"依次输入二叉树的结点数据："<<endl;CreatBiTree(root);cout<<"二叉树建立完成."<<endl;//cout<<"前序遍历二叉树."<<endl;//PreOrder(root);//cout<<"\n前序遍历二叉树完成."<<endl;//cout<<"层序遍历二叉树."<<endl;//LevelOrder(root);//cout<<"\n层序遍历二叉树完成."<<endl;cout<<"Solution类的层序遍历二叉树."<<endl;Solution example;vector<vector<int>> result;result=example.levelOrder(root);//for(auto &row:result)//for(auto ele:row)//cout<<ele<<" ";cout<<endl;system("pause");return 0;}