search/sort algos

# Search Algorithms

def linear_search(arr, target):
    """Linear Search: Find the index of target in the array (O(n))"""
    for i, val in enumerate(arr):
        if val == target:
            return i  # Return the index of the target
    return -1  # Return -1 if the target is not found

def binary_search(arr, target):
    """Binary Search: Find the index of target in a sorted array (O(log n))"""
    low, high = 0, len(arr) - 1
    while low <= high:
        mid = (low + high) // 2
        if arr[mid] == target:
            return mid  # Return the index of the target
        elif arr[mid] < target:
            low = mid + 1
        else:
            high = mid - 1
    return -1  # Return -1 if the target is not found

# Sorting Algorithms

def merge_sort(arr):
    """Merge Sort: Sort the array (O(n log n))"""
    if len(arr) <= 1:
        return arr
    mid = len(arr) // 2
    left = merge_sort(arr[:mid])
    right = merge_sort(arr[mid:])
    return merge(left, right)

def merge(left, right):
    """Merge two sorted lists"""
    result = []
    i, j = 0, 0
    while i < len(left) and j < len(right):
        if left[i] < right[j]:
            result.append(left[i])
            i += 1
        else:
            result.append(right[j])
            j += 1
    result.extend(left[i:])
    result.extend(right[j:])
    return result

def quick_sort(arr):
    """Quick Sort: Sort the array (O(n log n) on average, O(n^2) in the worst case)"""
    if len(arr) <= 1:
        return arr
    pivot = arr[0]
    left = [x for x in arr[1:] if x < pivot]
    right = [x for x in arr[1:] if x >= pivot]
    return quick_sort(left) + [pivot] + quick_sort(right)

def bubble_sort(arr):
    """Bubble Sort: Sort the array (O(n^2))"""
    n = len(arr)
    for i in range(n):
        swapped = False
        for j in range(0, n - i - 1):
            if arr[j] > arr[j + 1]:
                arr[j], arr[j + 1] = arr[j + 1], arr[j]  # Swap elements
                swapped = True
        if not swapped:
            break  # If no elements were swapped, the list is sorted
    return arr

# Example Usage

# Search algorithms
arr = [3, 2, 1, 5, 4]
target = 5
print(f"Linear Search: Target {target} is at index {linear_search(arr, target)}")

arr_sorted = [1, 2, 3, 4, 5]
target = 4
print(f"Binary Search: Target {target} is at index {binary_search(arr_sorted, target)}")

# Sorting algorithms
arr_to_sort = [5, 2, 9, 1, 5, 6]
print(f"Original Array: {arr_to_sort}")

# Merge Sort
sorted_arr_merge = merge_sort(arr_to_sort)
print(f"Merge Sort: {sorted_arr_merge}")

# Quick Sort
sorted_arr_quick = quick_sort(arr_to_sort)
print(f"Quick Sort: {sorted_arr_quick}")

# Bubble Sort
sorted_arr_bubble = bubble_sort(arr_to_sort)
print(f"Bubble Sort: {sorted_arr_bubble}")