Added strings programs in data structure folder

Author: VeeruYadav45

data_structures/strings/allunique.py

@@ -0,0 +1,11 @@
+def has_unique_chars(s):
+    seen = set()
+    for char in s:
+        if char in seen:
+            return False
+        seen.add(char)
+    return True
+
+# Example
+s = "abcdefga"
+print("Unique Characters:", has_unique_chars(s))

data_structures/strings/anagram.py

@@ -0,0 +1,7 @@
+from collections import Counter
+
+def are_anagrams(s1, s2):
+    return Counter(s1) == Counter(s2)
+
+# Example
+print("Anagram:", are_anagrams("listen", "silent"))

data_structures/strings/frequencyofeachchar.py

@@ -0,0 +1,8 @@
+def char_frequency(s):
+    freq = {}
+    for char in s:
+        freq[char] = freq.get(char, 0) + 1
+    return freq
+
+# Example
+print(char_frequency("datastructure"))

data_structures/strings/reverseword.py

@@ -0,0 +1,10 @@
+def reverse_words(sentence):
+    words = sentence.split()
+    stack = []
+    for word in words:
+        stack.append(word)
+    reversed_sentence = ' '.join(stack[::-1])
+    return reversed_sentence
+
+# Example
+print(reverse_words("Data Structures in Python"))