AlgoDatSoSe24/SoSe24/lec05_hash/hash_table.py

from SoSe24.algodat.foundation import AlgoDatArray, AlgoDatValue, read_int_sequence, MinusInf
from time import perf_counter as pfc

#Goldener Schnitt
import math
a = (math.sqrt(5) - 1) / 2
explore_steps = 0

def h(x, m):
    return int(x*a - int(x*a) * m)


def f(x, i, m):
    return (h(x, m) + i + 14*i*i) % m


def f1(x, i, m):
    if i % 2 == 0:
        return (h(x, m) + i*i) % m
    return ((h(x, m) - i*i) % m + m) % m


class HashTable:
    def __init__(self, m, hash_function, exploratory_function=None):
        self.m = m
        self.h = hash_function
        self.f = exploratory_function
        self.n = 0
        self.table = AlgoDatArray(m)

    def insert(self, x):
        global explore_steps
        i = 0
        while i < self.m:
            j = self.f(x.value, i, self.m)
            if self.is_free(j):
                self.table[j].value = x.value
                self.n += 1
                return True
            i += 1
            explore_steps += 1
        return False

    def search(self, x):
        global explore_steps
        i = 0
        while i < self.m:
            j = f(x, i, self.m)
            if self.table[j] == x:
                return True
            if self.table[j] == None:
                return False
            i += 1
            explore_steps += 1
        return False

    def delete(self, x):
        global explore_steps
        i = 0
        while i < self.m:
            j = f(x, i, self.m)
            if self.table[j].value == x:
                self.table[j].value = "DELETED"
                self.n -= 1
                return True
            if self.table[j].value is None:
                return False
            i += 1
            explore_steps += 1
        return False

    def __str__(self):
        return str(self.table)

    def alpha(self):
        return self.n / self.m

    def is_free(self, i):
        if self.table[i] == None:
            return True
        if  self.table[i] == "DELETED":
            return True
        return False


if __name__ == "__main__":
    z = read_int_sequence("../../seq1.txt")
    start = pfc()
    hash = HashTable(31, h, f)
    for algodat_value in z:
        hash.insert(algodat_value)
    print(hash)
    print(f"Alpha: {hash.alpha()}")
    hash.delete(11)
    hash.search(47)
    hash.search(243)
    print(hash)
    print(f"Alpha: {hash.alpha()}")
    print(f"Dauer: {pfc() - start:.4f}s")
    print(f"Sondierungsschritte: {explore_steps}")
    AlgoDatValue.summary()