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wk3assn.py
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wk3assn.py
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import os
import logging
import array
from typing import Tuple, AnyStr
from itertools import repeat
import math
log_level = os.getenv("LOG_LEVEL", "INFO") # TODO: make fix wrt this in some nice way
log_level = {
"CRITICAL": logging.CRITICAL,
"INFO": logging.INFO,
"DEBUG": logging.DEBUG,
}.get(log_level)
LOGGER = logging.getLogger(__name__)
FORMAT = "[%(filename)s:%(lineno)3s - %(funcName)25s() ] %(message)s"
logging.basicConfig(format=FORMAT)
LOGGER.setLevel(log_level)
def swap(arr, i, j):
if i != j:
_temp = arr[i]
arr[i] = arr[j]
arr[j] = _temp
if LOGGER.isEnabledFor(logging.DEBUG):
LOGGER.debug(
f"{arr} \t| swapped arr[{i}]={arr[j]} <--> arr[{j}]={arr[i]}: "
)
def partition(arr: array.ArrayType, l: int, r: int) -> Tuple[int, int]:
if LOGGER.isEnabledFor(logging.DEBUG):
LOGGER.debug(f"{arr} \t| l={l}, r={r} \t\t| size of subarr: {str(r-l):2s}")
p = arr[l]
i = l + 1
for j in range(l + 1, r + 1):
if arr[j] < p:
# swap i and j index
swap(arr, i, j)
i += 1
# final pivot swap
if LOGGER.isEnabledFor(logging.DEBUG):
LOGGER.debug(f"{arr} \t| Placing pivot {p: >3d} at pos {i - 1} ({p-1})")
swap(arr, l, i - 1)
return r - l, i - 1
def quicksort_and_count_first(arr: array.ArrayType, start: int, stop: int) -> int:
if LOGGER.isEnabledFor(logging.DEBUG):
LOGGER.debug(
f"{arr} \t| Quicksort: arr[{start:>2}:{stop+1: <2}] --> \t| {list(arr[start:stop+1])}"
)
if stop - start < 1:
return 0
m_p, i_p = partition(arr, start, stop)
# sort first part
if LOGGER.isEnabledFor(logging.DEBUG):
LOGGER.debug(
f"{arr} \t| Partition done:\t| pivot={arr[i_p]} i_p={i_p} m_p={m_p} "
)
m_1 = quicksort_and_count_first(arr, start=start, stop=i_p - 1)
m_2 = quicksort_and_count_first(arr, start=i_p + 1, stop=stop)
if LOGGER.isEnabledFor(logging.DEBUG):
LOGGER.debug(f" m_p + m_1 + m_2 = {m_p}+{m_1}+{m_2}={m_p + m_1 + m_2}")
return m_p + m_1 + m_2
def quicksort_and_count_last(arr: array.ArrayType, start: int, stop: int) -> int:
if LOGGER.isEnabledFor(logging.DEBUG):
LOGGER.debug(
f"{arr} \t| Quicksort: arr[{start:>2}:{stop+1: <2}] --> \t| {list(arr[start:stop+1])}"
)
if stop - start < 1:
return 0
swap(arr, start, stop)
m_p, i_p = partition(arr, start, stop)
# sort first part
if LOGGER.isEnabledFor(logging.DEBUG):
LOGGER.debug(
f"{arr} \t| Partition done:\t| pivot={arr[i_p]} i_p={i_p} m_p={m_p} "
)
m_1 = quicksort_and_count_last(arr, start=start, stop=i_p - 1)
m_2 = quicksort_and_count_last(arr, start=i_p + 1, stop=stop)
if LOGGER.isEnabledFor(logging.DEBUG):
LOGGER.debug(f" m_p + m_1 + m_2 = {m_p}+{m_1}+{m_2}={m_p + m_1 + m_2}")
return m_p + m_1 + m_2
def get_piv_idx_med(arr, start, stop):
# idx_mid = start + round((stop - start) / 2 )
if stop - start % 2 == 1: # even length array,
# LOGGER.debug("Even length array")
idx_mid = int(start + (stop - start + 1) / 2)
else: # odd length array
# LOGGER.debug("Odd length array")
idx_mid = int(start + (stop - start) / 2)
if LOGGER.isEnabledFor(logging.DEBUG):
LOGGER.debug(
f"{arr} \t| Pivot cands: 1: arr[{start}, {idx_mid}, {stop}] " # = {arr[start]}, {arr[idx_mid]}, {arr[stop]} "
)
if idx_mid in (start, stop):
return idx_mid
median_array = sorted([ (arr[start], start), (arr[idx_mid], idx_mid), (arr[stop], stop)])
return median_array[1][1]
# _t = arr[start], arr[stop], arr[idx_mid]
# for idx in start, stop, idx_mid:
# if arr[idx] < max(_t) and arr[idx] > min(_t):
# return idx
def quicksort_and_count_med(arr: array.ArrayType, start: int, stop: int) -> int:
if LOGGER.isEnabledFor(logging.DEBUG):
LOGGER.debug(
f"{arr} \t| Quicksort: arr[{start:>2}:{stop+1: <2}] --> \t| {list(arr[start:stop+1])}"
)
if stop - start < 1:
return 0
# set pivot (1st el) as median of right left and middle element
_idx_piv = get_piv_idx_med(arr, start, stop)
if LOGGER.isEnabledFor(logging.DEBUG):
LOGGER.debug(f"{arr} \t| Pivot el arr[{_idx_piv}]={arr[_idx_piv]}")
swap(arr, start, _idx_piv)
m_p, i_p = partition(arr, start, stop)
# sort first part
if LOGGER.isEnabledFor(logging.DEBUG):
LOGGER.debug(
f"{arr} \t| Partition done:\t| pivot={arr[i_p]} i_p={i_p} m_p={m_p} "
)
m_1 = quicksort_and_count_med(arr, start=start, stop=i_p - 1)
m_2 = quicksort_and_count_med(arr, start=i_p + 1, stop=stop)
if LOGGER.isEnabledFor(logging.DEBUG):
LOGGER.debug(
f"{arr} \t| Quicksort: arr[{start:>2}:{stop+1: <2}] --> \t| m_p + m_1 + m_2 = {m_p}+{m_1}+{m_2}={m_p + m_1 + m_2}"
)
return m_p + m_1 + m_2
if __name__ == "__main__":
from pathlib import Path
from ast import literal_eval
import argparse
import sys
from copy import deepcopy
sys.setrecursionlimit(10000000) # TODO: comment away ifneed
LOGGER.critical("Recursion limit: " + str(sys.getrecursionlimit()))
parser = argparse.ArgumentParser(
prog="Number of comparisons in quicksort",
)
parser.add_argument("--spec", help="", default="(4, 5, 2, 3, 1)") # should give 7
# parser.add_argument("--spec", help="", default="(3, 2, 0, 4, 1, 7, 6, 5)")
args = parser.parse_args()
if Path(args.spec).exists():
numbers = Path(args.spec).read_text().splitlines()
else:
numbers = literal_eval(args.spec)
LOGGER.info(f"Found {len(numbers)} numbers in array")
arr = array.array("I", map(int, numbers))
if LOGGER.isEnabledFor(logging.DEBUG):
LOGGER.debug(str(arr) + " <-- original")
ans_first = quicksort_and_count_first(deepcopy(arr), start=0, stop=len(arr) - 1)
ans_last = quicksort_and_count_last(deepcopy(arr), start=0, stop=len(arr) - 1)
ans_med = quicksort_and_count_med(deepcopy(arr), start=0, stop=len(arr) - 1)
LOGGER.critical("ANSWER:")
LOGGER.critical(f"FIRST : {ans_first}")
LOGGER.critical(f"LAST : {ans_last}")
LOGGER.critical(f"MEDIAN: {ans_med}")