Павел
106 lines
3.2 KiB
Python
106 lines
3.2 KiB
Python
from copy import deepcopy
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from ipaddress import IPv4Address
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from typing import List, Tuple
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from itertools import groupby
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from collections import defaultdict
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def get_data(input_file):
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with open(input_file, "r") as file:
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data = file.read().splitlines()
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return data
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def cidr4_to_binary(cidr4: str) -> str:
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ip_str, vlsm = cidr4.strip().split("/")
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vlsm = int(vlsm)
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ipv4 = IPv4Address(ip_str)
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binary_ip = bin(int(ipv4))[2:]
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binary_ip = binary_ip.zfill(32)
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binary = binary_ip[:vlsm] + "0" * (32 - vlsm)
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return binary
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def binary_to_cidr4(binary: str) -> str:
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vlsm = binary.rfind("1") + 1 if "1" in binary else 0
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int_ip = int(binary, 2)
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ip = IPv4Address(int_ip)
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return f"{ip}/{vlsm}"
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def reduce_binary(binary: str) -> str:
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assert len(binary) == 32
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vlsm = binary.rfind("1")
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if vlsm == -1:
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return binary
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return binary[:vlsm] + "0" + binary[vlsm + 1 :]
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def rough_merge_binaries(binaries: List[str], req_len: int) -> List[str]:
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ips = set(deepcopy(binaries))
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non_reducible_ips = set()
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reduction_limit_reached = False
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max_vlsm = float("inf")
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while (
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len(ips) > 0
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and len(ips) + len(non_reducible_ips) > req_len
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and not reduction_limit_reached
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and max_vlsm != -1
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):
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ip_with_max_vlsm = max(ips, key=lambda x: x.rfind("1"))
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max_vlsm = ip_with_max_vlsm.rfind("1")
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reduced_ips = set()
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merged_ips = set()
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for ip in ips:
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if ip.rfind("1") == max_vlsm:
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reduced_ip = reduce_binary(ip)
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if "1" in reduced_ip:
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reduced_ips.add(reduced_ip)
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else:
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non_reducible_ips.add(ip)
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else:
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merged_ips.add(ip)
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merged_ips.update(reduced_ips)
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if len(merged_ips) + len(non_reducible_ips) > req_len:
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ips = merged_ips
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else:
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reduction_limit_reached = True
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ips.update(non_reducible_ips)
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return sorted(ips)
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def main():
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file = "cidr4.txt"
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required_len = 20
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data = get_data(file)
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bin_ips = list(map(cidr4_to_binary, data))
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rough_merged_bin_ips = rough_merge_binaries(bin_ips, required_len)
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print(f"{len(rough_merged_bin_ips)=}")
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for ip in rough_merged_bin_ips:
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print(ip)
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if __name__ == "__main__":
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assert cidr4_to_binary("4.78.139.0/24") == "00000100010011101000101100000000"
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assert cidr4_to_binary("128.0.0.0/1") == "10000000000000000000000000000000"
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assert cidr4_to_binary("0.0.0.0/0") == "0" * 32
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assert cidr4_to_binary("0.8.0.0/13") == "00000000000010000000000000000000"
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assert binary_to_cidr4("00000100010011101000101100000000") == "4.78.139.0/24"
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assert binary_to_cidr4("10000000000000000000000000000000") == "128.0.0.0/1"
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assert binary_to_cidr4("00000000000000000000000000000000") == "0.0.0.0/0"
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assert binary_to_cidr4("00000000000010000000000000000000") == "0.8.0.0/13"
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assert (
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reduce_binary("00000100010011101000101100000000")
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== "00000100010011101000101000000000"
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)
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assert reduce_binary("10000000000000000000000000000000") == "0" * 32
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assert reduce_binary("0" * 32) == "0" * 32
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assert reduce_binary("00000000000010000000000000000000") == "0" * 32
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main()
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