Write a program to find the node at which the intersection of two singly linked lists begins.
For example, the following two linked lists:
A: a1 → a2 ↘ c1 → c2 → c3 ↗ B: b1 → b2 → b3
begin to intersect at node c1.
Notes:
null
.
Credits:
Special thanks to @stellari for adding this problem and creating all test cases.
/** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */ class Solution { public: ListNode *getIntersectionNode(ListNode *headA, ListNode *headB) { if(headA==NULL || headB==NULL) return NULL; //Ensure the start point isn't in the cycle; //Create a cycle in head B; ListNode* temp = headB; while(temp->next!=NULL) { if(temp == headA) return headA; temp = temp->next; } ListNode* tailB = temp; temp->next = headB; ListNode* slow = headA; ListNode* fast = headA; while(fast!=NULL && fast->next!=NULL) { slow = slow->next; fast = fast->next; fast = fast->next; if(fast==slow) break; } if(fast == NULL || fast->next==NULL) { tailB->next = NULL; return NULL; } fast = headA; while(fast!=slow) { fast = fast->next; slow = slow->next; } tailB->next = NULL; return slow; } };
LeetCode--Intersection of Two Linked Lists
原文地址:http://blog.csdn.net/shaya118/article/details/42774681