[Oracle] LeetCode 160 Intersection of Two Linked Lists

Given the heads of two singly linked-lists headA and headB, return the node at which the two lists intersect. If the two linked lists have no intersection at all, return null.

Solution

我们直接用 \(map\) 来保存 \(ListNode*\) 是否存在。

点击查看代码

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode(int x) : val(x), next(NULL) {}
 * };
 */
class Solution {
private:
    unordered_map<ListNode*,int> mp;
public:
    ListNode *getIntersectionNode(ListNode *headA, ListNode *headB) {
        while(headA){
            mp[headA]=1;
            headA=headA->next;
        }
        while(headB){
            if(mp[headB])return headB;
            headB = headB->next;
        }
        return NULL;
    }
};