- /** 这个可太难想到了，双指针法！
- * Definition for singly-linked list.
- * struct ListNode {
- * int val;
- * ListNode *next;
- * ListNode(int x) : val(x), next(NULL) {}
- * };
- */
- auto speedup=[](){
- std::ios::sync_with_stdio(false);
- cin.tie(nullptr);
- cout.tie(nullptr);
- return nullptr;
- }();
- class Solution {
- public:
- ListNode *getIntersectionNode(ListNode *headA, ListNode *headB) {
- /**
- a
- - c
- b /
- a->end : a+c a移到b head
- b->end : b+c b移到a head
- 会在a+b+c 步之后再交汇点相遇
- 如果有交点 会在交点相会
- 如果没有交点会同时到达NULL
- */
- if(headA == NULL || headB == NULL){
- return NULL;
- }
- ListNode * la = headA;
- ListNode * lb = headB;
- while(la != lb){
- la = la ? la->next : headB;
- lb = lb ? lb->next : headA;
- }
- return la;
- }
-
};
来自 <http://www.planetb.ca/projects/syntaxHighlighter/popup.php>