Add simple linear search algorithm

Author: AmeySGajare

searches/linear_search_simple.py

@@ -0,0 +1,107 @@
+"""
+Linear Search Algorithm
+
+Linear search (also known as sequential search) is a simple searching algorithm
+that checks each element in a collection sequentially until it finds the target
+value or reaches the end of the collection.
+
+How it works:
+1. Start from the first element in the collection
+2. Compare the current element with the target value
+3. If they match, return the index of the current element
+4. If they don't match, move to the next element
+5. Repeat steps 2-4 until the target is found or all elements have been checked
+6. If the target is not found after checking all elements, return -1
+
+Time Complexity:
+- Best case: O(1) - when the target is found at the first position
+- Average case: O(n) - where n is the number of elements
+- Worst case: O(n) - when the target is at the end or not found
+
+Space Complexity:
+- O(1) - only a constant amount of extra space is used (for variables)
+"""
+
+
+from typing import Any, List, Optional
+
+
+def linear_search(collection: List[Any], target: Any) -> int:
+    """
+    Perform a linear search to find the target value in the collection.
+
+    Args:
+        collection: A list of elements to search through (does not need to be sorted)
+        target: The value to search for in the collection
+
+    Returns:
+        The index of the target value if found, -1 otherwise
+
+    Examples:
+        >>> linear_search([5, 2, 8, 1, 9], 8)
+        2
+        >>> linear_search([5, 2, 8, 1, 9], 3)
+        -1
+        >>> linear_search(['apple', 'banana', 'cherry'], 'banana')
+        1
+    """
+    for index, item in enumerate(collection):
+        if item == target:
+            return index
+    return -1
+
+
+if __name__ == "__main__":
+    # Example 1: Searching for a number in a list of integers
+    numbers = [64, 34, 25, 12, 22, 11, 90]
+    target_number = 22
+    result = linear_search(numbers, target_number)
+    
+    print("Example 1: Searching for a number")
+    print(f"Collection: {numbers}")
+    print(f"Target: {target_number}")
+    if result != -1:
+        print(f"Result: Found at index {result}")
+    else:
+        print("Result: Not found")
+    print()
+
+    # Example 2: Searching for a string
+    fruits = ["apple", "banana", "cherry", "date", "elderberry"]
+    target_fruit = "cherry"
+    result = linear_search(fruits, target_fruit)
+    
+    print("Example 2: Searching for a string")
+    print(f"Collection: {fruits}")
+    print(f"Target: {target_fruit}")
+    if result != -1:
+        print(f"Result: Found at index {result}")
+    else:
+        print("Result: Not found")
+    print()
+
+    # Example 3: Target not found
+    numbers = [1, 3, 5, 7, 9]
+    target_number = 4
+    result = linear_search(numbers, target_number)
+    
+    print("Example 3: Target not found")
+    print(f"Collection: {numbers}")
+    print(f"Target: {target_number}")
+    if result != -1:
+        print(f"Result: Found at index {result}")
+    else:
+        print("Result: Not found")
+    print()
+
+    # Example 4: Empty collection
+    empty_list: List[int] = []
+    result = linear_search(empty_list, 5)
+    
+    print("Example 4: Empty collection")
+    print(f"Collection: {empty_list}")
+    print(f"Target: 5")
+    if result != -1:
+        print(f"Result: Found at index {result}")
+    else:
+        print("Result: Not found")