Day102.cpp

// Intersection of Linked Lists

// https://www.interviewbit.com/problems/intersection-of-linked-lists/

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
ListNode* Solution::getIntersectionNode(ListNode* A, ListNode* B) {
    // Do not write main() function.
    // Do not read input, instead use the arguments to the function.
    // Do not print the output, instead return values as specified
    // Still have a doubt. Checkout www.interviewbit.com/pages/sample_codes/ for more details
    
    ListNode* l1 = A;
    ListNode* l2 = B;
   
    while(l1 != l2) {
        if(l1 == NULL) {
            l1 = B;
        }
        else {
            l1 = l1 -> next;
        }
        if(l2 == NULL) {
           l2 = A;
        }
        else {
           l2 = l2 -> next;
        }
    }
    if(l1 != NULL) {
        return l1;
    }
    
}