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.
求两个链表的交集。这里应该注意，如果在一个节点两个链表相交了，那么之后的节点也是相交的，所以我们可以这么做：
扫描到链表A或者链表B的末尾时，将A的尾部指针指向B的头，将B的尾部指针指向A的头，知道找到相同的节点
/** * 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) { ListNode *p1 = headA; ListNode *p2 = headB; bool mark1 = false; bool mark2 = false; while(p1 != nullptr && p2 != nullptr) { if (p1 == p2) return p1; p1 = p1->next; p2 = p2->next; if (p1 == nullptr && !mark1) p1 = headB,mark1 = true; if (p2 == nullptr && !mark2) p2 = headA,mark2 = true; } return nullptr; } };
160. Intersection of Two Linked Lists
原文：http://www.cnblogs.com/pk28/p/7239186.html