URI 1195-Binary Search Tree

/**
  *  @Author: Pranta Sarker
  *
  **/


#include<bits/stdc++.h>

using namespace std;

#define fast ios_base::sync_with_stdio(0)
#define bfast cin.tie(0)
#define outs(x) cout << x << " "
#define outn(x) cout << x << "\n"
#define sf scanf
#define pf printf
#define pfn(x , k) printf(k , x)
#define nl puts("")
#define psb push_back
#define mset(c,v) memset(c , v , sizeof c)
#define loop0(n) for(int i=0; i<n; i++)
#define loop1(n) for(int i=1; i<=n; i++)
#define mpair(x , y) make_pair(x , y)
#define all(x) x.begin(), x.end()
#define pi acos(-1.0)
#define psb push_back
#define clr clear()

typedef unsigned long long ull;
typedef long long LL;
typedef vector<int>vii;
typedef vector<LL>vll;
typedef vector<string>vs;
typedef map<int, int>mpii;
typedef map<string, int>mpsi;
typedef map<char, int>mpci;
typedef map<LL, LL>mpll;

const int mod = 1000007;
const int high = 1002;

struct Node
{
    int key;
    Node *left, *right;
};

Node *newNode(int data)
{
    Node *tmp = new Node;

    tmp->key = data;
    tmp->left = tmp->right = NULL;
    return tmp;
}

Node *Insert(Node *root, int data)
{
    if(root == NULL) return newNode(data);
    else if(root->key < data) root->right = Insert(root->right , data);
    else if(root->key > data) root->left =  Insert(root->left , data);

    return root;
}

bool space = false;

void Inorder(Node *root)
{
    if(root)
    {
        Inorder(root->left);
        if(!space)
        {
            cout << root->key;
            space=true;
        }

        else
        {
            cout << " " << root->key;
        }
        Inorder(root->right);
    }
}

void Postorder(Node *root)
{
    if(root)
    {
        Postorder(root->left);
        Postorder(root->right);
        if(!space)
        {
            cout << root->key;
            space=true;
        }

        else
        {
            cout << " " << root->key;
        }
    }
}

void Preorder(Node *root)
{
    if(root)
    {
        if(!space)
        {
            cout << root->key;
            space=true;
        }

        else
        {
            cout << " " << root->key;
        }


        Preorder(root->left);
        Preorder(root->right);
    }
}

int main()
{
    fast;
    int test , tc=0;
    cin >> test;
    while(test--)
    {
        Node *root = NULL;
        int i , x , N;
        cin >> N;
        cin >> x;
        root = Insert(root, x);

        for(i=1; i<N; i++)
        {
            cin >> x;
            Insert(root , x);
        }

        cout << "Case " << ++tc << ":\n";

        space = false;

        cout << "Pre.: ";

        Preorder(root);

        cout << "\n";

        space = false;

        cout << "In..: ";

        Inorder(root);

        cout << "\n";

        space = false;
        cout << "Post: ";

        Postorder(root);

        cout << "\n\n";

    }

    return 0;
}