Array - 23: Intersection of Two UnSorted arrays | Find common elements of two UnSorted arrays

Solution:
- Take a set & one by one put all values of first array
- Now, iterate 2nd array & check if it present in 1st array, put this value in another new Set (i.e finalSet)
- At last, all unique common elments will be present in finalSet
- Time Complexity: O(n + m) for iterating the both array, where m - first array length, m - second array length

Please check video for more info:

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[laurawu]

very good solution and very detail analysis

[tusharnain]

Yes, you are right, basically all the solutions on internet prints the duplicate values/

[fatmabadran]

Is this solution works also with 3 unsorted arrays? Does it give comlexity O(n)?

[gajendralnmiit]

You dont need to take final set. Once you encounter an element of arr2 in the set, print that element and remove it from the set.

[singhmanish]

It will be wrong. If there are 2 same elements in both the set.
ex= {4 4}, {1 4 2 3 5 4}

[mohitkumar-zcwd]

What if common elements are repeated in both array. Then we will have to take hashmap and store frequency of each element of first array. while traversing second array will decrease frequency whenever we encounter common element. {1 2 2 3} and {2 2 5 3} intersection would be {2 2 3}

[sarahdaniel]

Thankyou for this solution, but this exceeds time limit on GeeksforGeeks.