solves #2605: Form Smallest Number From Two Digit Arrays in java

Author: anishLearnsToCode

README.md

@@ -810,7 +810,7 @@
 | 2591 | [Distribute Money to Maximum Children](https://leetcode.com/problems/distribute-money-to-maximum-children)                                                             |                                                                              [![Java](assets/java.png)](src/DistributeMoneyToMaximumChildren.java)                                                                               |                                                                                                                                   |
 | 2595 | [Number of Even and Odd Bits](https://leetcode.com/problems/number-of-even-and-odd-bits)                                                                               |                                                                                   [![Java](assets/java.png)](src/NumberOfEvenAndOddBits.java)                                                                                    |                                                                                                                                   |
 | 2600 | [K Items With the Maximum Sum](https://leetcode.com/problems/k-items-with-the-maximum-sum)                                                                             |                                                                                   [![Java](assets/java.png)](src/KItemsWithTheMaximumSum.java)                                                                                   |                                                                                                                                   |
-| 2605 | [Form Smallest Number From Two Digit Arrays](https://leetcode.com/problems/form-smallest-number-from-two-digit-arrays)                                                 |                                                                                                                                                                                                                                  |                                                                                                                                   |
+| 2605 | [Form Smallest Number From Two Digit Arrays](https://leetcode.com/problems/form-smallest-number-from-two-digit-arrays)                                                 |                                                                            [![Java](assets/java.png)](src/FormSmallestNumberFromTwoDigitArrays.java)                                                                             |                                                                                                                                   |
 | 2605 | [Form Smallest Number From Two Digit Arrays](https://leetcode.com/problems/form-smallest-number-from-two-digit-arrays)                                                 |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 2609 | [Find the Longest Balanced Substring of a Binary String](https://leetcode.com/problems/find-the-longest-balanced-substring-of-a-binary-string)                         |                                                                                                                                                                                                                                  |                                                                                                                                   |
 | 2614 | [Prime In Diagonal](https://leetcode.com/problems/prime-in-diagonal)                                                                                                   |                                                                                                                                                                                                                                  |                                                                                                                                   |

src/FormSmallestNumberFromTwoDigitArrays.java

@@ -0,0 +1,58 @@
+// https://leetcode.com/problems/form-smallest-number-from-two-digit-arrays
+// T: O(N log(N) + M log(M))
+// S: O(log(N) + log(M))
+
+import java.util.Arrays;
+import java.util.HashSet;
+import java.util.Set;
+
+public class FormSmallestNumberFromTwoDigitArrays {
+    public int minNumber(int[] nums1, int[] nums2) {
+        final Set<Integer> intersection = intersection(nums1, nums2);
+
+        if (!intersection.isEmpty()) {
+            final int[] digits = toArray(intersection);
+            Arrays.sort(digits);
+            return digits[0];
+        }
+
+        Arrays.sort(nums1);
+        Arrays.sort(nums2);
+        final int smallerDigit = Math.min(nums1[0], nums2[0]);
+        final int largerDigit = Math.max(nums1[0], nums2[0]);
+        return smallerDigit * 10 + largerDigit;
+    }
+
+    private Set<Integer> intersection(int[] array1, int[] array2) {
+        final Set<Integer> set1 = toSet(array1);
+        final Set<Integer> set2 = toSet(array2);
+        return intersection(set1, set2);
+    }
+
+    private Set<Integer> toSet(int[] array) {
+        final Set<Integer> set = new HashSet<>();
+        for (int element : array) {
+            set.add(element);
+        }
+        return set;
+    }
+
+    private Set<Integer> intersection(Set<Integer> set1, Set<Integer> set2) {
+        final Set<Integer> set = new HashSet<>();
+        for (int element : set1) {
+            if (set2.contains(element)) {
+                set.add(element);
+            }
+        }
+        return set;
+    }
+
+    private int[] toArray(Set<Integer> set) {
+        final int[] array = new int[set.size()];
+        int index = 0;
+        for (int element : set) {
+            array[index++] = element;
+        }
+        return array;
+    }
+}