PatientBST.java

/*
 * Click nbfs://nbhost/SystemFileSystem/Templates/Licenses/license-default.txt to change this license
 * Click nbfs://nbhost/SystemFileSystem/Templates/Classes/Class.java to edit this template
 */
package hospitalmanagementsystem;

/**
 *
 * @author egehanhatipoglu
 */

public class PatientBST {

   
    // INNER CLASS: BSTNode
   
    private class BSTNode {
        Patient patient;
        BSTNode left;
        BSTNode right;

        BSTNode(Patient patient) {
            this.patient = patient;
            this.left = null;
            this.right = null;
        }
    }

    private BSTNode root;

    public PatientBST() {
        this.root = null;
    }

   
    // INSERT
   
    public void insert(Patient patient) {
        root = insertRec(root, patient);
    }

    private BSTNode insertRec(BSTNode node, Patient patient) {
    if (node == null) {
        return new BSTNode(patient);
    }

    String newPatientName = patient.getFirstName() + " " + patient.getLastName();
    String nodeName = node.patient.getFirstName() + " " + node.patient.getLastName();

    // küçük → sol
    if (newPatientName.compareToIgnoreCase(nodeName) < 0) {
        node.left = insertRec(node.left, patient);
    }
    // büyük → sağ
    else if (newPatientName.compareToIgnoreCase(nodeName) > 0) {
        node.right = insertRec(node.right, patient);
    }
    // ← DEĞİŞİKLİK: Eşitse reddet (AVL ile tutarlı)
    // else durumunda hiçbir şey yapma - duplikayı ekleme
    
    return node;
}
    
    
    // PatientBST.java sınıfına eklenecek DELETE metodu

// ============================================
// DELETE
// ============================================
public boolean delete(String firstName, String lastName) {
    int initialSize = countNodes(root);
    root = deleteRec(root, firstName, lastName);
    int finalSize = countNodes(root);
    return finalSize < initialSize; // Silme başarılı mı kontrol et
}

private BSTNode deleteRec(BSTNode node, String firstName, String lastName) {
    if (node == null) {
        return null;
    }

    String targetName = firstName + " " + lastName;
    String nodeName = node.patient.getFirstName() + " " + node.patient.getLastName();

   
    if (targetName.compareToIgnoreCase(nodeName) < 0) {
        node.left = deleteRec(node.left, firstName, lastName);
    }
    // Sağ alt ağaca git
    else if (targetName.compareToIgnoreCase(nodeName) > 0) {
        node.right = deleteRec(node.right, firstName, lastName);
    }
    // Düğüm bulundu - sil
    else {
        // Durum 1: Yaprak düğüm (çocuk yok)
        if (node.left == null && node.right == null) {
            return null;
        }
        
        // Durum 2: Tek çocuk var
        if (node.left == null) {
            return node.right;
        }
        if (node.right == null) {
            return node.left;
        }
        
        // Durum 3: İki çocuk var
        // Sağ alt ağaçtaki en küçük değeri bul (inorder successor)
        BSTNode successor = findMin(node.right);
        
        // Successor'ın verisini bu düğüme kopyala
        node.patient = successor.patient;
        
        // Successor'ı sil
        node.right = deleteRec(node.right, 
                              successor.patient.getFirstName(), 
                              successor.patient.getLastName());
    }
    
    return node;
}

// En küçük değeri bulma (en soldaki düğüm)
   private BSTNode findMin(BSTNode node) {
           while (node.left != null) {
        node = node.left;
    }
    return node;
}

// Düğüm sayısını hesaplama (delete kontrolü için)
     private int countNodes(BSTNode node) {
    if (node == null) return 0;
    return 1 + countNodes(node.left) + countNodes(node.right);
}
    
    
    
    

    // ============================================
    // SEARCH
    // ============================================
    public Patient search(String firstName, String lastName) {
        return searchRec(root, firstName, lastName);
    }

    private Patient searchRec(BSTNode node, String firstName, String lastName) {
        if (node == null) {
            return null;
        }

        String searchNewPatientName = firstName + " " + lastName;
        String nodeName =  node.patient.getFirstName() + " " + node.patient.getLastName();
                

        // bulundu
        if (searchNewPatientName.equalsIgnoreCase(nodeName)) {
            return node.patient;
        }

        // küçük → sol
        if (searchNewPatientName.compareToIgnoreCase(nodeName) < 0) {
            return searchRec(node.left, firstName, lastName);
        }
        // büyük → sağ
        else {
            return searchRec(node.right, firstName, lastName);
        }
    }

    // ============================================
    // DISPLAY (IN-ORDER)
    // ============================================
    public void displayInOrder() {
        if (root == null) {
            System.out.println("  BST is empty.");
            return;
        }

        System.out.println("=== Patients (Alphabetical Order) ===");
        displayInOrderRec(root);
    }

    private void displayInOrderRec(BSTNode node) {
        if (node != null) {
            displayInOrderRec(node.left);

            Patient p = node.patient;
            System.out.println(
                "  " + p.getFirstName() + " " + p.getLastName() +
                " (ID: " + p.getId() +
                ", National ID: " + p.getNationalId() + ")"
            );

            displayInOrderRec(node.right);
        }
    }
}