Intersection of Multiple Arrays

Author: shashankvishwakarma

src/main/java/leetcode/easy/IntersectionOfMultipleArrays.java

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+package leetcode.easy;
+
+import java.util.*;
+
+/**
+ * https://leetcode.com/problems/intersection-of-multiple-arrays/description/
+ * <p>
+ * Example 1:
+ * Input: nums = [[3,1,2,4,5],[1,2,3,4],[3,4,5,6]]
+ * Output: [3,4]
+ * Explanation:
+ * The only integers present in each of nums[0] = [3,1,2,4,5], nums[1] = [1,2,3,4], and nums[2] = [3,4,5,6] are 3 and 4, so we return [3,4].
+ * <p>
+ * Example 2:
+ * Input: nums = [[1,2,3],[4,5,6]]
+ * Output: []
+ * Explanation:
+ * There does not exist any integer present both in nums[0] and nums[1], so we return an empty list [].
+ */
+public class IntersectionOfMultipleArrays {
+    public static void main(String[] args) {
+
+        // Test case 1
+        int[][] nums1 = {
+                {3, 1, 2, 4, 5},
+                {1, 2, 3, 4},
+                {3, 4, 5, 6}
+        };
+        List<Integer> result1 = intersection(nums1);
+        System.out.println("Intersection of nums1: " + result1);
+
+        // Test case 2
+        int[][] nums2 = {
+                {1, 2, 3},
+                {4, 5, 6}
+        };
+        List<Integer> result2 = intersection(nums2);
+        System.out.println("Intersection of nums2: " + result2);
+    }
+
+    public static List<Integer> intersection(int[][] nums) {
+        // Initialize a HashSet with the elements of the first array
+        Set<Integer> resultSet = new HashSet<>();
+        for (int num : nums[0]) {
+            resultSet.add(num);
+        }
+
+        // Iterate through the rest of the arrays and keep only the common elements
+        for (int i = 1; i < nums.length; i++) {
+            Set<Integer> currentSet = new HashSet<>();
+            for (int num : nums[i]) {
+                if (resultSet.contains(num)) {
+                    currentSet.add(num);
+                }
+            }
+            resultSet = currentSet; // Update the result set to only contain common elements
+        }
+
+        // Convert the result set to a list, sort it, and return it
+        List<Integer> resultList = new ArrayList<>(resultSet);
+        Collections.sort(resultList); // Sort the result in ascending order
+        return resultList;
+    }
+
+
+}