【PAT】A1099. Build A Binary Search Tree (30)

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

#pragma warning(disable:4996)
#include <stdio.h>
#include <stdlib.h>
#include <vector>
#include <queue>
#include <algorithm>
using namespace std;
const int maxn = 1010;
int n, data[maxn], left, right, index = 0;
vector<int> vnode[maxn], result;
typedef struct node{
	int data, right, left;
}node;
node nodes[maxn];
void inorder(int root){
	if (nodes[root].left != -1)
		inorder(nodes[root].left);
	nodes[root].data = data[index++];
	if (nodes[root].right != -1)
		inorder(nodes[root].right);
}
void levelorder(int root){
	queue<int> qi;
	qi.push(root);
	while (!qi.empty()){
		int now = qi.front();
		qi.pop();
		result.push_back(nodes[now].data);
		if (nodes[now].left != -1)	qi.push(nodes[now].left);
		if (nodes[now].right != -1)	qi.push(nodes[now].right);
	}
}
int main(){
	scanf("%d", &n);
	for (int i = 0; i < n; i++){
		scanf("%d %d", &left, &right);
		nodes[i].left = left;
		nodes[i].right = right;
	}
	for (int i = 0; i < n; i++)
		scanf("%d", &data[i]);
	sort(data, data + n);
	inorder(0);
	levelorder(0);
	for (int i = 0; i < n; i++){
		if (i)	printf(" ");
		printf("%d", result[i]);
	}
	printf("\n");
	system("pause");
	return 0;
}