In [8]:

    

def max_val(nums):
    mval = nums[0]
    for i in nums:
        if mval < i:
            mval = i
            
    return mval

b = [30, 1, 2, 4, 7, 9]

print max_val(b)


    

    




30

In [6]:

    

def min_val(nums):
    mval = nums[0]
    for i in nums:
        if mval > i:
            mval = i
    return mval
b = [30,2,4]
print min_val(b)


    

    




2

In [14]:

    

a = [1, 10, 4, 5, 6]
a.sort(reverse = True)
a


    

    
Out[14]:





[10, 6, 5, 4, 1]

In [15]:

    

def merge_sort(arr, desc = False):
    if len(arr) <= 1: return arr      # only 2 or more
    half = len(arr) // 2              # divide by 2
    L = merge_sort(arr[:half], desc)  # Left: first half
    R = merge_sort(arr[half:], desc)  # Right: except first half
    mer = []                          # array for result
      
    while len(L) > 0 and len(R) > 0:
        if (L[0] > R[0] and not desc) or (L[0] < R[0] and desc):
            mer.append(R[0]);  R.pop(0)  # append R[0] and remove
        else:
            mer.append(L[0]);  L.pop(0)  # append L[0] and remove
    # if out of L or R, append rest
    if len(L) > 0: mer += L
    if len(R) > 0: mer += R
    return mer    # return


    

In [16]:

    

unsorted = [6, 4, 1, 7, 8, 5, 2, 3]
print("  Unsorted: %s" % unsorted)
print(" Ascending: %s" % merge_sort(unsorted) )
print("Descending: %s" % merge_sort(unsorted, True) )


    

    




  Unsorted: [6, 4, 1, 7, 8, 5, 2, 3]
 Ascending: [1, 2, 3, 4, 5, 6, 7, 8]
Descending: [8, 7, 6, 5, 4, 3, 2, 1]