Isograms

Instructions

An isogram is a word that has no repeating letters, consecutive or non-consecutive.

Implement a function that determines whether a string that contains only letters is an isogram.

Assume the empty string is an isogram. Ignore letter case.

Example:

isIsogram "Dermatoglyphics" == true
isIsogram "moose" == false
isIsogram "aba" == false

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My Solution

import java.util.Set;
import java.util.stream.Collectors;

public class Isogram {

    public static boolean isIsogram(String str) {
        Set<Integer> uniqueChars = str.toLowerCase().chars()
                .boxed()
                .collect(Collectors.toSet());

        return str.length() == uniqueChars.size();
    }
}

Better Solution

public class IsogramSolution {
    public static boolean isIsogram(String str) {
        return str.length() == str.toLowerCase().chars().distinct().count();
    }
}

Feeling

나름 잘했다고 생각했는데 distinct().count()를 몰라서 이런식으로 사용가능 할 줄 몰랐다…

Stream 관련해서 얼마나 아느냐도 알고리즘 문제푸는데 중요할 것 같다.