In [49]:

    

def quick_sort(mylist):
    if len(mylist) <= 1:
        return mylist
    
    pivot = mylist[0]
    
    less = [x for x in mylist if x < pivot]
    more = [x for x in mylist if x > pivot]
    pivotList = [x for x in mylist if x == pivot]
            
    less = quickSort(less)
    more = quickSort(more)
    
    return less + pivotList + more

a = [4, 65, 2, -31, 0, 99, 83, 782, 1]
print(a, " -> ", quick_sort(a))


    

    




[4, 65, 2, -31, 0, 99, 83, 782, 1]  ->  [-31, 0, 1, 2, 4, 65, 83, 99, 782]

In [52]:

    

def find(data, key, l, r, default):
    if r < 1:
        return default
    
    midpoint = 1 + (r - l) // 2
     
    if key < data[midpoint]:
        return find(data, key, 1, midpoint - 1, default)
    if key > data[midpoint]:
        return find(data, key, midpoint + 1, r, default)
    else:
        return midpoint
    
a = quick_sort([4, 65, 2, -31, 0, 99, 83, 782, 1])
print(a)

print(find(a, -31, 0, len(a)-1, -999))


    

    




[-31, 0, 1, 2, 4, 65, 83, 99, 782]
-999

In [78]:

    

def first_and_last(l, item):
    first, last = -1, -1
    
    for i in range(len(l)):
        if l[i] == item:
            if first == -1:
                first = i
            last = i
            
    return first, last

    
print(first_and_last([1, 3, 6, 7, 7, 7 ,88, 103, 426], 7))


    

    




(3, 5)

In [101]:

    

def find(data, key, l, r, default):
    if r < 1:
        return default
    
    midpoint = 1 + (r - l) // 2
     
    if key < data[midpoint]:
        return find(data, key, 1, midpoint - 1, default)
    if key > data[midpoint]:
        return find(data, key, midpoint + 1, r, default)
    else:
        return midpoint
    
def binary_first_and_last(data, key):
    first = last = find(data, key, 0, len(data)-1, -1)
    
    while data[first-1] == key:
        first = first - 1
    
    while data[last+1] == key:
        last = last + 1
    
    return first, last
    
        
print(binary_first_and_last([1, 3, 6, 7, 7, 7 ,88, 103, 426], 7))


    

    




(3, 5)

In [ ]: