Mr. Duck's BST - Hard Construction Solution

#include <bits/stdc++.h>
using namespace std;

const int N = 1010;
int pre[N];

struct node {
    node *left;
    node *right;
    int data;
};

node *solve(int l, int r) {
    if (l > r)
        return NULL;
    node *root = new node;
    root->data = pre[l];
    for (int i = l+1; i <= r+1; ++i) {
        if (pre[i] > pre[l] || i == r+1) {
            root->left = solve(l+1, i-1);
            root->right = solve(i, r);
            break;
        }
    }
    return root;
}

void postorder(node *root) {
    if (root == NULL)
        return;
    postorder(root->left);
    postorder(root->right);
    printf("%d ", root->data);
}

int main()
{
    int n;
    scanf("%d", &n);
    for (int i = 0; i < n; ++i)
        scanf("%d", &pre[i]);

    node *root = solve(0, n-1);
    postorder(root);

    return 0;
}