CodeFights : first duplicate

Author: Karolina Kafel

src/main/java/com/other/FirstDuplicate.java

@@ -0,0 +1,13 @@
+package com.other;
+
+class FirstDuplicate {
+
+    static int firstDuplicate(int[] a) {
+        boolean[] duplicates = new boolean[(int) (Math.pow(10, 5)+1)];
+        int i = 0;
+        while(i < a.length && !duplicates[a[i]]){
+            duplicates[a[i++]] = true;
+        }
+        return i < a.length && duplicates[a[i]] ? a[i] : -1;
+    }
+}

src/test/java/com/other/FirstDuplicateTest.java

@@ -0,0 +1,15 @@
+package com.other;
+
+import org.junit.Test;
+
+import static com.other.FirstDuplicate.firstDuplicate;
+import static org.assertj.core.api.Assertions.assertThat;
+
+public class FirstDuplicateTest {
+
+    @Test
+    public void failingCase13() {
+        int[] a = new int[]{28, 19, 13, 6, 34, 48, 50, 3, 47, 18, 15, 34, 16, 11, 13, 3, 2, 4, 46, 6, 7, 3, 18, 9, 32, 21, 3, 21, 50, 10, 45, 13, 22, 1, 27, 18, 3, 27, 30, 44, 12, 30, 40, 1, 1, 31, 6, 18, 33, 5};
+        assertThat(firstDuplicate(a)).isEqualTo(34);
+    }
+}