🐍 4.5: Python ile Linked List

from collections import deque

print("🔄 collections.deque Kullanımı\n")

# Oluşturma
d = deque(['A', 'B', 'C'])
print(f"Başlangıç: {list(d)}")

# Başa ve sona ekleme - O(1)
d.appendleft('X')  # Başa
d.append('Y')      # Sona
print(f"X başa, Y sona: {list(d)}")

# Baştan ve sondan silme - O(1)
d.popleft()  # Baştan
d.pop()      # Sondan
print(f"Baş ve son silindi: {list(d)}")

# Rotate - Circular gibi döndürme!
d = deque([1, 2, 3, 4, 5])
print(f"\nRotate öncesi: {list(d)}")

d.rotate(2)  # Sağa 2 döndür
print(f"rotate(2): {list(d)}")

d.rotate(-3)  # Sola 3 döndür
print(f"rotate(-3): {list(d)}")

# Maxlen - Sabit boyutlu (LRU Cache gibi!)
print(f"\n📦 Sabit boyutlu deque (maxlen=3):")
limited = deque(maxlen=3)
for i in range(5):
    limited.append(i)
    print(f"  append({i}): {list(limited)}")

from collections import deque print("🔄 collections.deque Kullanımı\n") d = deque(['A', 'B', 'C']) print(f"Başlangıç: {list(d)}") d.appendleft('X') d.append('Y') print(f"X başa, Y sona: {list(d)}") d.popleft() d.pop() print(f"Baş ve son silindi: {list(d)}") # Rotate d = deque([1, 2, 3, 4, 5]) print(f"\nRotate öncesi: {list(d)}") d.rotate(2) print(f"rotate(2): {list(d)}") # Maxlen print(f"\n📦 maxlen=3:") limited = deque(maxlen=3) for i in range(5): limited.append(i) print(f" append({i}): {list(limited)}")

import time
from collections import deque

N = 50000
print(f"🧪 Performans Testi: {N} işlem\n")
print("=" * 50)

# 1. LIST - Başa ekleme
liste = []
start = time.time()
for i in range(N):
    liste.insert(0, i)  # O(n) - her seferinde kaydırma!
list_insert_time = time.time() - start
print(f"📋 list.insert(0, x)  : {list_insert_time:.4f} sn")

# 2. DEQUE - Başa ekleme
kuyruk = deque()
start = time.time()
for i in range(N):
    kuyruk.appendleft(i)  # O(1) - sabit zaman!
deque_append_time = time.time() - start
print(f"🔄 deque.appendleft() : {deque_append_time:.4f} sn")

print(f"\n💡 Deque {list_insert_time/deque_append_time:.0f}x daha hızlı!")

print("\n" + "=" * 50)

# 3. LIST - Baştan silme
liste = list(range(N))
start = time.time()
while liste:
    liste.pop(0)  # O(n)
list_pop_time = time.time() - start
print(f"📋 list.pop(0)        : {list_pop_time:.4f} sn")

# 4. DEQUE - Baştan silme
kuyruk = deque(range(N))
start = time.time()
while kuyruk:
    kuyruk.popleft()  # O(1)
deque_pop_time = time.time() - start
print(f"🔄 deque.popleft()    : {deque_pop_time:.4f} sn")

print(f"\n💡 Deque {list_pop_time/deque_pop_time:.0f}x daha hızlı!")

print("\n" + "=" * 50)
print("\n📊 SONUÇ:")
print("  - Başa ekleme/silme → deque kullan!")
print("  - Random access (index) → list kullan!")
print("  - Sona ekleme/silme → ikisi de O(1)")

import time from collections import deque N = 50000 print(f"🧪 Performans: {N} işlem\n") # LIST vs DEQUE - Başa ekleme liste = [] start = time.time() for i in range(N): liste.insert(0, i) list_time = time.time() - start print(f"📋 list.insert(0): {list_time:.4f} sn") kuyruk = deque() start = time.time() for i in range(N): kuyruk.appendleft(i) deque_time = time.time() - start print(f"🔄 deque.appendleft: {deque_time:.4f} sn") print(f"\n💡 Deque {list_time/deque_time:.0f}x hızlı!")

from collections import deque

class LinkedList:
    """deque tabanlı LinkedList wrapper"""
    
    def __init__(self, iterable=None):
        self._data = deque(iterable) if iterable else deque()
    
    def prepend(self, value):
        """Başa ekle - O(1)"""
        self._data.appendleft(value)
    
    def append(self, value):
        """Sona ekle - O(1)"""
        self._data.append(value)
    
    def pop_first(self):
        """Baştan sil - O(1)"""
        if not self._data:
            raise IndexError("Liste boş!")
        return self._data.popleft()
    
    def pop_last(self):
        """Sondan sil - O(1)"""
        if not self._data:
            raise IndexError("Liste boş!")
        return self._data.pop()
    
    @property
    def head(self):
        """İlk eleman"""
        return self._data[0] if self._data else None
    
    @property
    def tail(self):
        """Son eleman"""
        return self._data[-1] if self._data else None
    
    def __len__(self):
        return len(self._data)
    
    def __iter__(self):
        return iter(self._data)
    
    def __repr__(self):
        return f"LinkedList({list(self._data)})"

# Test
print("🔗 LinkedList Wrapper Demo\n")

ll = LinkedList([1, 2, 3])
print(f"Başlangıç: {ll}")

ll.prepend(0)
ll.append(4)
print(f"0 başa, 4 sona: {ll}")

print(f"Head: {ll.head}, Tail: {ll.tail}")

print(f"pop_first(): {ll.pop_first()}")
print(f"pop_last(): {ll.pop_last()}")
print(f"Sonuç: {ll}")

print(f"\nİterasyon:")
for item in ll:
    print(f"  → {item}")

from collections import deque class LinkedList: def __init__(self, iterable=None): self._data = deque(iterable) if iterable else deque() def prepend(self, value): self._data.appendleft(value) def append(self, value): self._data.append(value) def pop_first(self): return self._data.popleft() if self._data else None def pop_last(self): return self._data.pop() if self._data else None @property def head(self): return self._data[0] if self._data else None @property def tail(self): return self._data[-1] if self._data else None def __repr__(self): return f"LinkedList({list(self._data)})" ll = LinkedList([1, 2, 3]) print(f"Start: {ll}") ll.prepend(0) ll.append(4) print(f"After: {ll}") print(f"Head: {ll.head}, Tail: {ll.tail}")