二叉树的结构

https://www.acwing.com/problem/content/description/4274/

#include<bits/stdc++.h>
#include<string.h>
using namespace std;
const int N = 1010;
int post[N], in[N], pos[N];
int l[N], r[N], f[N];
int depth[N];
int n, m;

int build(int pl, int pr, int il, int ir)
{
	int root = post[pr];
	int k = pos[root];

	if (k > il)
	{
		int t = build(pl, pr - 1 - (ir - k - 1) - 1, il, k - 1);
		l[root] =t;
		f[t] = root;
	}
	if (k < ir)
	{
		int t = build(pr - 1 - (ir - k - 1), pr - 1, k + 1, ir);
		r[root] = t;
		f[t] = root;
	}

	return root;
}

void dfs(int root,int u)
{
	if (root == 0) return;
	depth[root] = u;
	if(l[root])dfs(l[root], u + 1);
	if(r[root])dfs(r[root], u + 1);
}

bool check(int root)
{
	if (root == 0) return true;
	if ((l[root] != 0 && r[root] != 0) || ((l[root] == 0 && r[root] == 0)))
	{
		
		return check(l[root]) && check(r[root]);;
	}
	else
	{
		return false;
	}
}

int main()
{
	cin >> n;
	for (int i = 1; i <= n; i++) cin >> post[i]; 
	for (int i = 1; i <= n; i++) cin >> in[i], pos[in[i]] = i;
	int root = build(1, n, 1, n);
	dfs(root,1);
	//cout<<root<<endl;
	//cout << r[2] << endl;
	cin >> m;
	getchar();
	string s;
	for (int i = 1; i <= m; i++)
	{
		getline(cin,s);
		if (s.find("root")!=-1)
		{
			stringstream ssin(s);
			vector<int> temp(2);
			sscanf(s.c_str(), "%d", &temp[0]);
			cout << (temp[0]== root ? "Yes" : "No") << endl;
		}
		if (s.find("siblings") != -1)
		{
			stringstream ssin(s);
			vector<int> temp(2);
			sscanf(s.c_str(), "%d and %d", &temp[0], &temp[1]);
			if (temp[0] != temp[1]) cout << (f[temp[0]]==f[temp[1]] ? "Yes" : "No") << endl;
			else cout << "No" << endl;
		}
		if (s.find("parent") != -1)
		{
			vector<int> temp(2);
			stringstream ssin(s);
			sscanf(s.c_str(), "%d is the parent of %d", &temp[0], &temp[1]);
			cout << (temp[0] == f[temp[1]] ? "Yes" : "No") << endl;
		}
		if (s.find("left") != -1)
		{
			vector<int> temp(2);
			stringstream ssin(s);
			sscanf(s.c_str(), "%d is the left child of %d", &temp[0], &temp[1]);
			cout << (temp[0] == l[temp[1]] ? "Yes" : "No") << endl;
		}
		if (s.find("right") != -1)
		{
			vector<int> temp(2);
			stringstream ssin(s);
			sscanf(s.c_str(), "%d is the right child of %d", &temp[0], &temp[1]);
			cout << (temp[0] == r[temp[1]] ? "Yes" : "No") << endl;
		}
		if (s.find("level") != -1)
		{
			vector<int> temp(2);
			stringstream ssin(s);
			sscanf(s.c_str(), "%d and %d", &temp[0], &temp[1]);
			cout << (depth[temp[0]] == depth[temp[1]] ? "Yes" : "No") << endl;
		}
		if (s.find("full") != -1)
		{
			cout << (check(root) == true ? "Yes" : "No") << endl;
		}
	}
	return 0;
}