标签:面试题
travel the binary tree by level 5 ( from down to top and from left to right every level )
个人信息:就读于燕大本科软件工程专业 目前大三;
本人博客:google搜索“cqs_2012”即可;
个人爱好:酷爱数据结构和算法,希望将来从事算法工作为人民作出自己的贡献;
博客内容:travel the binary tree by level 5 ( from down to top and from left to right every level )
博客时间:2014-5-4;
编程语言:C++ ;
编程坏境:Windows 7 专业版 x64;
编程工具:vs2008 32位编译器;
制图工具:office 2010 ppt;
硬件信息:7G-3 笔记本;
my words
Money can be stolen, but not knowledge. Studying benefits me forever.
problem( from beauty of programming )
my solutiontravel the binary tree by level, and visit nodes form left to right every level.
make the function: int TravelByLevel(node * root, int level)
eg: the binary tree follows
the 2 level nodes: 3,7,12,15
first action: make tree stored with a two-dimensional table like following
then getting nodes of every level becomes very easy.
time cost O(n), n is the numbers node of the binary tree, and this algorithm is faster than that algorithm with queue and stack which I proposed yesterday.
function follows( we assume the binary tree is not so big, or new more space just ok)
int _TravelByLevel(node * T,int level) { cout<<"travel start level "<<level<<endl; // first action table * table_tree = new table[length]; queue<std::pair<node *,int>> Q; if(T != NULL) Q.push(std::make_pair(T,0)); // second action std::pair<node*,int> p; while(! Q.empty()) { // first action: 2.1 p = Q.front(); Q.pop(); ((table_tree[p.second]).list)[( (table_tree[p.second]).num)++] = p.first; // second action: 2.2 if((p.first)->left != NULL) Q.push(std::make_pair((p.first)->left,p.second+1)); if((p.first)->right != NULL) Q.push(std::make_pair((p.first)->right,p.second+1)); } // third action node * p1; if( level < length && table_tree[level].num > 0 ) { for(int j =0;j<(table_tree[level]).num;j++) { p1 = ((table_tree[level]).list)[j]; cout<<p1->data<<endl; } cout<<"travel over"<<endl; return 1; } cout<<"travel over"<<endl; return 0; }program run out:
my code
test.cpp
#include<iostream> #include<queue> #include<stack> using namespace std; const int length = 100; //const int Longlength = 10000; class node { public: int data ; node * left ; node * right ; node() { data = 0 ; left = right = NULL ; } }; class table { public: int num; node ** list; table(){ num = 0; list = new node*[length]; } }; void _MakeTree(node * &T,int *data,int length); void _Insert(node * & T,int data); void _Visit(node * T); int _TravelByLevel(node * T,int level); void _MakeTree(node * &T,int *data,int length) { for(int i=0;i<length;i++) { _Insert(T,data[i]); } } void _Insert(node * & T,int data) { if(T == NULL) { T = new node(); T -> data = data; } else { node * p = T; while(p != NULL) { if(data == p->data ) break; else if(data < p->data ) { if(p->left != NULL) { p = p ->left; } else{ p->left = new node(); (p->left) ->data = data; break; } } else{ if(p->right != NULL) p = p->right; else{ p->right = new node() ; (p->right) ->data = data ; break ; } } } } } int _TravelByLevel(node * T,int level) { cout<<"travel start level "<<level<<endl; // first action table * table_tree = new table[length]; queue<std::pair<node *,int>> Q; if(T != NULL) Q.push(std::make_pair(T,0)); // second action std::pair<node*,int> p; while(! Q.empty()) { // first action: 2.1 p = Q.front(); Q.pop(); ((table_tree[p.second]).list)[( (table_tree[p.second]).num)++] = p.first; // second action: 2.2 if((p.first)->left != NULL) Q.push(std::make_pair((p.first)->left,p.second+1)); if((p.first)->right != NULL) Q.push(std::make_pair((p.first)->right,p.second+1)); } // third action node * p1; if( level < length && table_tree[level].num > 0 ) { for(int j =0;j<(table_tree[level]).num;j++) { p1 = ((table_tree[level]).list)[j]; cout<<p1->data<<endl; } cout<<"travel over"<<endl; return 1; } cout<<"travel over"<<endl; return 0; } void _Visit(node * T) { if(T != NULL) cout<< T->data <<endl; else cout<<"visit NULL"<<endl; } int main() { int data[] = {8,6,3,7,2,1,13,12,15,17}; node * T = NULL; _MakeTree(T,data,10); for(int i= 0;i<5;i++) _TravelByLevel(T,i); system("pause"); return 0; }
travel the binary tree by level 5 ( from down to top and from left to right every level )
标签:面试题
原文地址:http://blog.csdn.net/cqs_experiment/article/details/25030671