Find The First Node Of Loop in Linked List

⭐ IN THE GIVEN PROBLEM, WE NEED TO RETURN THE FIRST NODE OF LINKED LIST THAT FORM A LOOP.
⭐ APPROACH: FIRST WE CHECK , IS THERE ANY LOOP FORM IN LIST OR NOT.
⭐ FOR THAT WE TAKE 2-POINTER NODE SLOW AND FAST , WHERE SLOW MOVE BY 1STEP AND FAST NODE MOVE BY 2X STEP, IF FAST IS EQUAL TO SLOW NODE, THAT MEANS IT FORMS A LOOP , ELSE NOT.
⭐ IF THE LIST HAVE A LOOP, NOW WE NEED TO CHECK FOR THE FIRST NODE OF LOOP.
⭐ FOR THAT WE NEED TO CHCEK THE CONDITON IF SLOW IS NOT EQUAL TO FAST.
⭐ WE NEED TO TRAVESE FAST AND SLOW NODE BY 1 STEP, AND WHILE TRAVESING IF FAST NODE IS NOT EQUAL TO SECOND NODE, THAT REPRESENT THE FIRST NODE OF LIST .
⭐ TIME COMPLEXITY: O(n)
⭐ SPACE COMPLEXITY: O(1)