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Python 3.14 - Complexity & Optimizations¶

Python 3.14 was released October 2025 with new max-heap support and continued performance improvements.

New Features Affecting Complexity¶

Max-Heap Support in heapq¶

Python 3.14 adds native max-heap functions to the heapq module:

import heapq

# New max-heap operations (Python 3.14+)
data = [3, 1, 4, 1, 5, 9, 2, 6]

heapq.heapify_max(data)          # O(n) - Transform to max-heap
heapq.heappush_max(data, 10)     # O(log n) - Add to max-heap
max_val = heapq.heappop_max(data) # O(log n) - Remove and return max
heapq.heapreplace_max(data, 7)   # O(log n) - Pop max, push new
heapq.heappushpop_max(data, 8)   # O(log n) - Push, then pop max

# Previously required negation workaround:
# Old: heapq.heappush(heap, -value)  # Negate for max-heap
# New: heapq.heappush_max(heap, value)  # Direct max-heap

Operation	Time	Space	Notes
`heapify_max(x)`	O(n)	O(1)	In-place max-heap transformation
`heappush_max(heap, item)`	O(log n)	O(1)	Add item to max-heap
`heappop_max(heap)`	O(log n)	O(1)	Remove and return max item
`heapreplace_max(heap, item)`	O(log n)	O(1)	Pop max then push
`heappushpop_max(heap, item)`	O(log n)	O(1)	Push then pop max

New Type Conversion Methods¶

# float.from_number() - O(1)
f = float.from_number(42)      # Converts number to float
f = float.from_number(3.14)    # Returns float

# complex.from_number() - O(1)  
c = complex.from_number(42)    # Converts to complex

# Raises TypeError for non-numeric types (stricter than float())
try:
    float.from_number("3.14")
except TypeError:
    pass

bytes.fromhex() Enhancement¶

# Now accepts bytes input (previously only str)
data = bytes.fromhex(b"48656c6c6f")  # O(n)
data = bytearray.fromhex(b"48656c6c6f")  # O(n)

Performance Improvements¶

Incremental Garbage Collection (3.14.0 to 3.14.4)¶

Python 3.14.0 shipped an incremental garbage collector that collected the old generation in increments rather than in one pass. After reports of memory pressure in production it was reverted to the generational collector from 3.13 in 3.14.5, which is also the collector in Python 3.15. See the gc module.

asyncio Optimization¶

import asyncio

# 10-20% faster task scheduling
# Per-thread doubly linked list for tasks
# Reduced memory usage

async def main():
    tasks = [asyncio.create_task(work()) for _ in range(1000)]
    await asyncio.gather(*tasks)  # Faster scheduling

uuid Performance¶

import uuid

# uuid3() and uuid5(): ~40% faster for 16-byte names
# uuid4(): ~30% faster
name_uuid = uuid.uuid5(uuid.NAMESPACE_DNS, "example.com")
random_uuid = uuid.uuid4()  # 30% faster

zlib on Windows¶

import zlib

# Windows: Now uses zlib-ng for better performance
# All compression levels faster
# Note: Z_BEST_SPEED (level 1) may compress less than before
data = zlib.compress(b"data" * 1000, level=6)

Complexity Characteristics¶

All standard complexities preserved from 3.13:

Operation	Complexity	Status
`list.append()`	O(1) amortized	Unchanged
`dict[key]`	O(1) avg	Unchanged
`set.add()`	O(1) amortized	Unchanged
`heapq.heappush()`	O(log n)	Unchanged
`heapq.heappush_max()`	O(log n)	New

Deferred Annotation Evaluation (PEP 649)¶

# Annotations no longer evaluated at function definition time
# Reduces import overhead for heavily annotated code

def process(data: list[ComplexType]) -> Result:
    pass

# ComplexType not evaluated until annotations accessed
# Reduces memory for unused annotations

Deprecations¶

# Deprecated:
# - calendar.January/February (use calendar.JANUARY/FEBRUARY)
# - codecs.open() (use built-in open())
# - Passing complex as real/imag to complex()

# Pending removal:
# - typing._UnionGenericAlias (Python 3.17)

Recommendations¶

When to Use Max-Heap Functions¶

import heapq

# Use heapify_max() for priority queues needing max first
tasks = [(1, "low"), (5, "high"), (3, "medium")]
heapq.heapify_max(tasks)
urgent = heapq.heappop_max(tasks)  # (5, "high")

# Use for top-k smallest (maintain max-heap of k items)
def k_smallest(items, k):
    heap = items[:k]
    heapq.heapify_max(heap)
    for item in items[k:]:
        if item < heap[0]:
            heapq.heapreplace_max(heap, item)
    return sorted(heap)

When to Upgrade¶

Upgrade to 3.14 if: - ✅ Need native max-heap support - ✅ UUID-heavy workloads - ✅ Windows zlib performance matters

Stay on 3.13 if: - ✅ Production stability priority - ✅ Package compatibility concerns - ✅ Testing free-threading builds

End of Life¶

Release: October 2025
Bugfix Support: Until October 2027
Security Support: Until October 2030