pat1064. Complete Binary Search Tree (30)

1064. Complete Binary Search Tree (30)

时间限制
100 ms
内存限制
65536 kB
代码长度限制
16000 B
判题程序
Standard
作者
CHEN, Yue

A Binary Search Tree (BST) is recursively defined as a binary tree which has the following properties:

  • The left subtree of a node contains only nodes with keys less than the node's key.
  • The right subtree of a node contains only nodes with keys greater than or equal to the node's key.
  • Both the left and right subtrees must also be binary search trees.

A Complete Binary Tree (CBT) is a tree that is completely filled, with the possible exception of the bottom level, which is filled from left to right.

Now given a sequence of distinct non-negative integer keys, a unique BST can be constructed if it is required that the tree must also be a CBT. You are supposed to output the level order traversal sequence of this BST.

Input Specification:

Each input file contains one test case. For each case, the first line contains a positive integer N (<=1000). Then N distinct non-negative integer keys are given in the next line. All the numbers in a line are separated by a space and are no greater than 2000.

Output Specification:

For each test case, print in one line the level order traversal sequence of the corresponding complete binary search tree. All the numbers in a line must be separated by a space, and there must be no extra space at the end of the line.

Sample Input:
10
1 2 3 4 5 6 7 8 9 0
Sample Output:
6 3 8 1 5 7 9 0 2 4

提交代码

 

 1 #include<cstdio>
 2 #include<stack>
 3 #include<algorithm>
 4 #include<iostream>
 5 #include<stack>
 6 #include<set>
 7 #include<map>
 8 #include<cmath>
 9 using namespace std;
10 int line[1005],tree[1005];
11 void Build(int *line,int *tree,int n,int cur){
12     if(!n){
13         return;
14     }
15     int h=log(n)/log(2);
16     int x=n-(pow(2,h)-1);
17 
18     //cout<<"x: "<<x<<endl;
19 
20     if(x>pow(2,h-1)){
21        x=pow(2,h-1);
22     }
23 
24     //cout<<"x: "<<x<<endl;
25 
26     int l=pow(2,h-1)+x-1;
27 
28     //cout<<"l:  "<<l<<endl;
29 
30     tree[cur]=line[l];
31     Build(line,tree,l,cur*2+1);
32     Build(line+l+1,tree,n-l-1,cur*2+2);
33 }
34 int main(){
35     //freopen("D:\\INPUT.txt","r",stdin);
36     int n,i;
37     scanf("%d",&n);
38     for(i=0;i<n;i++){
39         scanf("%d",&line[i]);
40     }
41     sort(line,line+n);
42     Build(line,tree,n,0);
43     printf("%d",tree[0]);
44     for(i=1;i<n;i++){
45         printf(" %d",tree[i]);
46     }
47     printf("\n");
48     return 0;
49 }

 

posted @ 2015-09-05 17:01  Deribs4  阅读(201)  评论(0编辑  收藏  举报