can be done by UF too

Author: Arjiit

UnionFind/longestConsecutive.java

@@ -0,0 +1,27 @@
+class Solution {
+    public int longestConsecutive(int[] nums) {
+        /*
+            finding the first element of the consecutive sequence and then finding the next ones.
+            T.C- O(n)
+        */
+        HashSet<Integer> hm = new HashSet<>();
+        for (int i=0; i<nums.length; i++) {
+            hm.add(nums[i]);
+        }
+        int longest = 0;
+        
+        for (int num : hm) {
+            int key = num;
+            if(!hm.contains(key - 1)) {
+                int count = 1;
+                while(hm.contains(key + 1)) {
+                    count++;
+                    key++;
+                }
+                longest = Math.max(longest, count);
+            }
+        }
+        return longest;
+    }
+}
+