1099. Build A Binary Search Tree (30)

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 (<=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 format "left_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:

9
1 6
2 3
-1 -1
-1 4
5 -1
-1 -1
7 -1
-1 8
-1 -1
73 45 11 58 82 25 67 38 42

Sample Output:

58 25 82 11 38 67 45 73 42

 #include<stdio.h>
 #include<math.h>
 #include<set>
 #include<algorithm>
 #include<vector>
 #include<queue>
 using namespace std;

 struct node
 {
     int l,r,v;
 };

 node Tree[];
 vector<int> vv;
 int cnt = ;
 void inOder(int root)
 {
     if(Tree[root].l != -)
         inOder(Tree[root].l);
     Tree[root].v = vv[cnt++];
     if(Tree[root].r != -)
         inOder(Tree[root].r);
 }

 int main()
 {
     int n,tem;
     scanf("%d",&n);
     for(int i =  ;i < n;++i)
     {
         scanf("%d%d",&Tree[i].l,&Tree[i].r);
     }

     for(int i =  ;i < n;++i)
     {
         scanf("%d",&tem);
         vv.push_back(tem);
     }
     sort(vv.begin(),vv.end());
     inOder();
     queue<node> qq;
     qq.push(Tree[]);
     bool fir = ;
     while(!qq.empty())
     {
         node ntem = qq.front();
         qq.pop();
         if(fir)
         {
             fir = ;
             printf("%d",ntem.v);
         }
         else
         {
             printf(" %d",ntem.v);
         }
         if(ntem.l != -)
             qq.push(Tree[ntem.l]);
         if(ntem.r != -)
             qq.push(Tree[ntem.r]);
     }
     printf("\n");
     return ;
 }