Merge pull request AllAlgorithms#17 from beingadityak/master

abranhe · web-flow · commit 5fa8b96c0a88 · 2018-10-04T00:03:32.000-04:00
4 String Algorithms in Python
diff --git a/strings/anagram_search.py b/strings/anagram_search.py
@@ -0,0 +1,44 @@
+#!/usr/bin/env python3
+
+"""
+Pythonic Implementation of Anagram search
+"""
+
+__author__ = "Aditya Krishnakumar"
+
+import collections
+
+# remove whitespaces
+def remove_whitespace(string):
+    return ''.join(string.split())
+
+"""
+    Checks if two strings are anagrams of each other, ignoring any whitespace.
+    
+    First remove any whitespace and lower all characters of both strings.
+    Then create dictionaries of the counts of every character in each string.
+    As well as keep a set of all characters used in both strings.
+    Check to ensure every unique character are used in both strings the
+    same number of times.
+"""
+
+def is_anagram(string1, string2):
+    charCount1 = collections.Counter(remove_whitespace(string1.lower()))
+    charCount2 = collections.Counter(remove_whitespace(string2.lower()))
+
+    allChars = set(charCount1.keys())
+    allChars = allChars.union(charCount2.keys())
+
+    for c in allChars:
+        if (charCount1[c] != charCount2[c]):
+            return False
+
+    return True
+
+# Dry runs
+
+assert is_anagram("anagram", "not a gram") == False
+assert is_anagram("anagram", "na a marg") == True
+assert is_anagram("William Shakespeare", "I am \t a weakish speller") == True
+assert is_anagram("Madam Curie", "Radium came") == True
+assert is_anagramg("notagram", "notaflam") == False
diff --git a/strings/morse_code.py b/strings/morse_code.py
@@ -0,0 +1,69 @@
+#!/usr/bin/env python
+"""
+Pythonic Implementation of Morse Code encoding
+"""
+
+__author__ = "Aditya Krishnakumar"
+
+
+# The alphabet dictionary for morse codes
+morseAlphabet = {
+    "A": ".-",
+    "B": "-...",
+    "C": "-.-.",
+    "D": "-..",
+    "E": ".",
+    "F": "..-.",
+    "G": "--.",
+    "H": "....",
+    "I": "..",
+    "J": ".---",
+    "K": "-.-",
+    "L": ".-..",
+    "M": "--",
+    "N": "-.",
+    "O": "---",
+    "P": ".--.",
+    "Q": "--.-",
+    "R": ".-.",
+    "S": "...",
+    "T": "-",
+    "U": "..-",
+    "V": "...-",
+    "W": ".--",
+    "X": "-..-",
+    "Y": "-.--",
+    "Z": "--..",
+    "1": ".----",
+    "2": "..---",
+    "3": "...--",
+    "4": "....-",
+    "5": ".....",
+    "6": "-....",
+    "7": "--...",
+    "8": "---..",
+    "9": "----.",
+    "0": "-----"
+}
+
+# Lambda function for decoding the code to alphabet
+inverseAlphabet = reduce(lambda a, b: dict(a.items() + b.items()),
+                         [{
+                             morseAlphabet[k]: k
+                         } for k in morseAlphabet.keys()], {})
+
+
+def encode(_text):
+    return ' '.join([morseAlphabet[_c.upper()] for _c in _text[:]])
+
+
+def decode(_text):
+    return ''.join([inverseAlphabet[_c] for _c in _text.split(' ')])
+
+# Dry runner
+def test():
+    print decode(encode("TEST")) == "TEST"
+
+
+if __name__ == "__main__":
+    test()
diff --git a/strings/password_checker.py b/strings/password_checker.py
@@ -0,0 +1,29 @@
+#!/usr/bin/env python3
+
+import re, pyperclip
+
+password = pyperclip.paste()
+
+eightLettersRegex = re.compile(r'\S{8,}')
+oneUppercaseRegex = re.compile(r'[A-Z]')
+oneNumberRegex = re.compile(r'\d')
+
+check = {
+    eightLettersRegex: 'Your password must be 8 letters',
+    oneUppercaseRegex: 'Your password must have at least one uppercase Letter.',
+    oneNumberRegex: 'Your password must have at least one number.'
+}
+
+print('Analyzing your password.')
+
+count = 1
+for regex, msg in check.items():
+    mo = regex.search(password)
+    if mo == None:
+        print(msg)
+        break
+    if count == len(check):
+        print('Good! Your password is strong enough!')
+    count += 1
+
+print('End.')
diff --git a/strings/rabin_karp.py b/strings/rabin_karp.py
@@ -0,0 +1,46 @@
+#!/usr/local/bin/env python3
+
+# Rabin Karp Algorithm in python using hash values
+# d is the number of characters in input alphabet
+d = 2560
+
+
+def search(pat, txt, q):
+    M = len(pat)
+    N = len(txt)
+    i = 0
+    j = 0
+
+    p = 0
+    t = 0
+    h = 1
+
+    for i in range(M - 1):
+        h = (h * d) % q
+
+    for i in range(M):
+        p = (d * p + ord(pat[i])) % q
+        t = (d * t + ord(txt[i])) % q
+
+    for i in range(N - M + 1):
+        if p == t:
+            for j in range(M):
+                if txt[i + j] != pat[j]:
+                    break
+
+            j += 1
+            if j == M:
+                print("Pattern found at index " + str(i))
+
+        if i < N - M:
+            t = (d * (t - ord(txt[i]) * h) + ord(txt[i + M])) % q
+            if t < 0:
+                t = t + q
+
+
+# Driver program to test the above function
+txt = "ALL WORLDS IS A STAGE AND ALL OF US ARE A PART OF THE PLAY"
+pat = "ALL"
+
+q = 101  # A prime number
+search(pat, txt, q)
