Algo: Merge Sort

merge_sort.py

def merge_two(arr1, arr2):
    merged = []
    
    arr1_index = 0
    arr2_index = 0
    arr1_size = len(arr1)
    arr2_size = len(arr2)
    
    while (arr1_index < arr1_size and arr2_index < arr2_size):
        if (arr1[arr1_index] < arr2[arr2_index]):
            merged.append(arr1[arr1_index])
            arr1_index += 1
        else:
            merged.append(arr2[arr2_index])
            arr2_index += 1

    while (arr1_index < arr1_size):
        merged.append(arr1[arr1_index])
        arr1_index += 1
        
    while (arr2_index < arr2_size):
        merged.append(arr2[arr2_index])
        arr2_index += 1

    return merged


def merge_all(arrays):
    merged = []

    for arr in arrays:
        merged = merge_two(merged, arr)

    return merged


# Main
merge_two([2, 8, 15], [5, 9, 12, 17]) # [2, 5, 8, 9, 12, 15, 17]
merge_all([[2, 8, 15], [5, 9, 12, 17], [3, 10, 14]]) # [2, 3, 5, 8, 9, 10, 12, 14, 15, 17]