Python | Find common elements in three sorted arrays by dictionary intersection
Given three arrays sorted in non-decreasing order, print all common elements in these arrays.
Examples:
Input: ar1 = [1, 5, 10, 20, 40, 80]
ar2 = [6, 7, 20, 80, 100]
ar3 = [3, 4, 15, 20, 30, 70, 80, 120]
Output: [80, 20]
Input: ar1 = [1, 5, 5]
ar2 = [3, 4, 5, 5, 10]
ar3 = [5, 5, 10, 20]
Output: [5, 5]
We have existing solution for this problem please refer Find common elements in three sorted arrays link. We can solve this problem quickly in python using intersection of dictionaries. Approach is simple,
- First convert all three lists into dictionaries having elements as keys and their frequencies as value, using Counter() method.
- Now perform intersection operation for three dictionaries, this will result us dictionary having common elements among three array list with their frequencies.
# Function to find common elements in three # sorted arrays from collections import Counter def commonElement(ar1,ar2,ar3): # first convert lists into dictionary ar1 = Counter(ar1) ar2 = Counter(ar2) ar3 = Counter(ar3) # perform intersection operation resultDict = dict(ar1.items() & ar2.items() & ar3.items()) common = [] # iterate through resultant dictionary # and collect common elements for (key,val) in resultDict.items(): for i in range(0,val): common.append(key) print(common) # Driver program if __name__ == "__main__": ar1 = [1, 5, 10, 20, 40, 80] ar2 = [6, 7, 20, 80, 100] ar3 = [3, 4, 15, 20, 30, 70, 80, 120] commonElement(ar1,ar2,ar3) |
chevron_right
filter_none
Output:
[80, 20]
Recommended Posts:
- intersection_update() in Python to find common elements in n arrays
- Python counter and dictionary intersection example (Make a string using deletion and rearrangement)
- Python | Find common elements in list of lists
- Python program to find common elements in three lists using sets
- Python | Combine two dictionary adding values for common keys
- Python | Get items in sorted order from given dictionary
- Intersection of two arrays in Python ( Lambda expression and filter function )
- heapq in Python to print all elements in sorted order from row and column wise sorted matrix
- Python | Print the common elements in all sublists
- Python | Print all the common elements of two lists
- Program to print all distinct elements of a given integer array in Python | Ordered Dictionary
- Merge two sorted arrays in Python using heapq
- Python | Find the closest Key in dictionary
- Python | Find depth of a dictionary
- Python program to find the sum of all items in a dictionary
If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.
Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.
