5-1 Build A Binary Search Tree   (30分)

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.

Given the structure of a binary tree and a sequence of distinct integer keys, there is only one way to fill these keys into the tree so that the resulting tree satisfies the definition of a BST. You are supposed to output the level order traversal sequence of that tree. The sample is illustrated by Figure 1 and 2.

Input Specification:

Each input file contains one test case. For each case, the first line gives a positive integer N ($\le$100) which is the total number of nodes in the tree. The next N lines each contains the left and the right children of a node in the formatleft_index right_index, provided that the nodes are numbered from 0 to N-1, and 0 is always the root. If one child is missing, then -1 will represent the NULL child pointer. Finally N distinct integer keys are given in the last line.

Output Specification:

For each test case, print in one line the level order traversal sequence of that tree. All the numbers must be separated by a space, with no extra space at the end of the line.

Sample Input:

91 62 3-1 -1-1 45 -1-1 -17 -1-1 8-1 -173 45 11 58 82 25 67 38 42

Sample Output:

58 25 82 11 38 67 45 73 42

#include<stdio.h>#include<stdlib.h>#include<math.h>struct Tree{int num;int left;int right;};int main(void){int n, m, temp, x, top, k, number;scanf("%d",&n);struct Tree a[n], c[n];struct Tree T;int b[n], d[n];int front, rear;for(int i=0; i<n; i++){scanf("%d %d",&m,&x);a[i].left=m;a[i].right=x;}for(int i=0; i<n; i++){scanf("%d",&b[i]);}for(int i=0; i<n; i++){for(int j=0; j<n-1; j++){if(b[j]>b[j+1]){temp=b[j];b[j]=b[j+1];b[j+1]=temp;}}}number=0;top=0;k=0;while(top!=0||number!=-1){    while(number!=-1)    {    d[top++]=number;    number=a[number].left;    }    number=d[--top];    a[number].num=b[k++];    if(number!=-1)    {    number=a[number].right;}}number=0;c[0]=a[0];front=0;rear=1;while(front!=rear){number=c[front].left;if(number!=-1){c[rear++]=a[number];        }number=c[front++].right;if(number!=-1){    c[rear++]=a[number];    }}for(int i=0; i<n; i++){if(i!=n-1){printf("%d ",c[i].num);}else{printf("%d",c[i].num);}}}