Some updates

Author: manojbaishya

.idea/csv-editor.xml

@@ -22,4 +22,13 @@ public int[] twoSum(int[] nums, int target) {
         }
         return new int[] {};
     }
+
+    public int[] twoSumAlt(int[] nums, int target) {
+        Map<Integer, Integer> lookbehind = new HashMap<>();
+        for (int i = 0; i < nums.length; i++) {
+            if (lookbehind.containsKey(target - nums[i])) return new int[] {lookbehind.get(target - nums[i]), i};
+            lookbehind.put(nums[i], i);
+        }
+        return new int[] {};
+    }
 }

.idea/dataSources.xml

@@ -195,14 +195,40 @@ public ListNode getIntersectionNode(ListNode headA, ListNode headB) {
 
     public boolean hasCycle(ListNode head) {
         ListNode slow = head, fast = head;
-        while(fast != null && fast.next != null) {
+        while (fast != null && fast.next != null) {
             slow = slow.next;
             fast = fast.next.next;
             if (slow == fast) return true;
         }
         return false;
     }
 
+    public ListNode getNodeIfHasCycle(ListNode head) {
+        ListNode slow = head, fast = head;
+        while (fast != null && fast.next != null) {
+            slow = slow.next;
+            fast = fast.next.next;
+            if (slow == fast) return fast;
+        }
+        return null;
+    }
+
+    public ListNode detectCycle(ListNode head) {
+        if (head == null) return null;
+        ListNode fast = getNodeIfHasCycle(head);
+        if (fast == null) return null;
+
+        ListNode slow = head;
+        ListNode prev = fast;
+        while (slow != fast) {
+            prev = fast;
+            slow = slow.next;
+            fast = fast.next;
+        }
+        prev.next = null;
+        return slow;
+    }
+
     public ListNode reverseKGroup(ListNode head, int k) {
         ListNode dummy = null;
         ListNode next;

.idea/sqldialects.xml

@@ -0,0 +1,4 @@
+package org.dojo.algorithms;
+
+public class TreeProblems {
+}

src/main/java/org/dojo/algorithms/HashTables.java

@@ -0,0 +1,99 @@
+select id, engine_manufacturer_id as manufacturer, name, full_name, capacity, configuration, aspiration
+from engine e;
+
+select id,
+       name,
+       full_name,
+       country_id,
+       best_championship_position,
+       best_starting_grid_position,
+       best_race_result,
+       total_championship_wins,
+       total_race_entries,
+       total_race_starts,
+       total_race_wins,
+       total_1_and_2_finishes,
+       total_race_laps,
+       total_podiums,
+       total_podium_races,
+       total_points,
+       total_championship_points,
+       total_pole_positions,
+       total_fastest_laps
+from constructor c;
+
+
+select race_id,
+       type,
+       position_display_order,
+       position_number,
+       position_text,
+       driver_number,
+       driver_id,
+       constructor_id,
+       engine_manufacturer_id,
+       tyre_manufacturer_id,
+       practice_time,
+       practice_time_millis,
+       practice_gap,
+       practice_gap_millis,
+       practice_interval,
+       practice_interval_millis,
+       practice_laps,
+       qualifying_time,
+       qualifying_time_millis,
+       qualifying_q1,
+       qualifying_q1_millis,
+       qualifying_q2,
+       qualifying_q2_millis,
+       qualifying_q3,
+       qualifying_q3_millis,
+       qualifying_gap,
+       qualifying_gap_millis,
+       qualifying_interval,
+       qualifying_interval_millis,
+       qualifying_laps,
+       starting_grid_position_qualification_position_number,
+       starting_grid_position_qualification_position_text,
+       starting_grid_position_grid_penalty,
+       starting_grid_position_grid_penalty_positions,
+       starting_grid_position_time,
+       starting_grid_position_time_millis,
+       race_shared_car,
+       race_laps,
+       race_time,
+       race_time_millis,
+       race_time_penalty,
+       race_time_penalty_millis,
+       race_gap,
+       race_gap_millis,
+       race_gap_laps,
+       race_interval,
+       race_interval_millis,
+       race_reason_retired,
+       race_points,
+       race_pole_position,
+       race_qualification_position_number,
+       race_qualification_position_text,
+       race_grid_position_number,
+       race_grid_position_text,
+       race_positions_gained,
+       race_pit_stops,
+       race_fastest_lap,
+       race_driver_of_the_day,
+       race_grand_slam,
+       fastest_lap_lap,
+       fastest_lap_time,
+       fastest_lap_time_millis,
+       fastest_lap_gap,
+       fastest_lap_gap_millis,
+       fastest_lap_interval,
+       fastest_lap_interval_millis,
+       pit_stop_stop,
+       pit_stop_lap,
+       pit_stop_time,
+       pit_stop_time_millis,
+       driver_of_the_day_percentage
+from race_data
+order by race_id
+offset 10 fetch next 20 rows only;