smallest_number_greater_than_given_number.py

def find_local_max(arr, val):
    local_max = None
    local_max_indx = None
    for i, v in enumerate(arr):
        if not local_max and v < val:
            local_max = v
            local_max_indx = i
        elif v > local_max and v < val:
            local_max = v
            local_max_indx = i
    return local_max, local_max_indx


def func(n):
    prev = None
    cur = None
    digits = []
    remaining = []
    switching_point = None

    while n:
        prev = cur
        cur = n % 10
        n /= 10
        if not prev or cur <= prev:
            digits.append(cur)
            continue
        else:
            while n:
                remaining.append(n % 10)
                n /= 10
            switching_point = cur
            break
    
    if not switching_point:
        print('none available')
        return
    
    local_max, local_max_indx = find_local_max(digits, switching_point)
    remaining.reverse()
    remaining.append(local_max)
    digits = digits[0:local_max_indx] + digits[local_max_indx + 1:]
    digits = sorted(digits + [switching_point], reverse=True)
    print(int(''.join(map(str, remaining + digits))))

func(41732)
func(98764)
func(128728)
func(126)