1099.Build A Binary Search Tree [指定结构的二叉搜索树层序遍历]

我又又又想不出来了，一开始想的和那个完全二叉搜索树一样，中序遍历输出层序，结果他指定了结构，然后我就没转过来、、、

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<iostream>
	#include<vector>
	#include<algorithm>
	using namespace std;
	struct node {
		int data,l, r, index, layer;
	}a[100];
	int n, b[100]; int cnt = 0;
	bool cmp(node x,node y) {
		if (x.layer != y.layer) return x.layer < y.layer;
		else return x.index < y.index;
	}
	void getlevel(int root,int index,int layer) {
			if (a[root].l != -1)getlevel(a[root].l, index * 2 + 1, layer + 1);
			a[root] = { b[cnt++],a[root].l,a[root].r,index,layer };
			if (a[root].r != -1)getlevel(a[root].r, index * 2 + 2, layer + 1);
	}
	int main() {
		cin >> n;
		for (int i = 0; i < n; i++)
			cin >> a[i].l >> a[i].r;
		for (int i = 0; i < n; i++)
			cin >> b[i];
		sort(b, b + n);
		getlevel(0, 0, 1);
		sort(a, a + n, cmp);
		cout << a[0].data;
		for (int i = 1; i < n; i++)
			cout << " " << a[i].data;


	}