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FindOdd.java
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FindOdd.java
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package main.java.kyu6;
/**
* https://www.codewars.com/kata/54da5a58ea159efa38000836
*
* Find the odd int
*
* Details:
*
* Given an array, find the integer that appears an odd number of times.
*
* There will always be only one integer that appears an odd number of times.
*/
import org.junit.Test;
import java.util.Arrays;
import static org.junit.Assert.assertEquals;
public class FindOdd {
public static int findIt(int[] input) {
return Arrays.stream(input)
.distinct()
.filter(a -> Arrays.stream(input)
.filter(b -> a == b).count() % 2 > 0)
.reduce((a, b) -> {
throw new IllegalStateException();
})
.getAsInt();
}
@Test
public void findTest() {
assertEquals(5, FindOdd.findIt(new int[]{20, 1, -1, 2, -2, 3, 3, 5, 5, 1, 2, 4, 20, 4, -1, -2, 5}));
assertEquals(-1, FindOdd.findIt(new int[]{1, 1, 2, -2, 5, 2, 4, 4, -1, -2, 5}));
assertEquals(5, FindOdd.findIt(new int[]{20, 1, 1, 2, 2, 3, 3, 5, 5, 4, 20, 4, 5}));
assertEquals(10, FindOdd.findIt(new int[]{10}));
assertEquals(10, FindOdd.findIt(new int[]{1, 1, 1, 1, 1, 1, 10, 1, 1, 1, 1}));
assertEquals(1, FindOdd.findIt(new int[]{5, 4, 3, 2, 1, 5, 4, 3, 2, 10, 10}));
}
}