Find Duplicate Numbers from Array

find_duplicate-1.py

# we can use dictionary to store key-value pair
# by using this we can slove this problem in O(n) time complexity
# to do that we need to import Counter from collections module 

from collections import Counter

def find_duplicate(arr):
    dc = Counter(arr) # accoring to python's docs this will take O(n)
    
    for val, count in dc.items(): # this will take O(n)
        if count > 1:             # looking for an element which occure more 1 time
            print(val)

arr = [10,20,10,20,30,40,30,50] # original array
find_duplicate(arr) # this will print each value to new line
# the output will be 10 20 30