Amazon Interview Question: Given two different strings, ... | Glassdoor

Interview Question

Software Engineer Intern Interview

Given two different strings, find the common characters

  between the two. For example if string A is "hello" and string B is "elbow" the common characters would be ['e', 'l', 'o']. Give a method that returns unique or duplicate entries.

Interview Answer

2 Answers


Using python sets, create the two sets of characters, then return the intersection. This will return the set of characters that are in both strings.

from sets import Set

def duplicateChars(s1, s2):
    s1set = set()
    s2set = set()
    for c in s1:
    for c in s2:

    return s1set.intersection(s2set)

print duplicateChars("string", "ring")

Sam on Jan 10, 2014

Solution in Java:

public class StringIntersection {
    String str1 = "hello";
    String str2 = "elbow";

    public Set findIntersection() {
        String[] arr1 = str1.split("");
        String[] arr2 = str2.split("");

        List list = Arrays.asList(arr1);

        Set set = new LinkedHashSet(Arrays.asList(arr1));


        return set; // returns [e, l, o]

Chase on Jan 11, 2014

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