160 相交链表

https://leetcode.cn/leetbook/read/top-interview-questions-medium/xvpj16/

cost: 11m48s

/**
 * 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) {
        auto pA = headA, pB = headB;
        bool jumpA = false, jumpB = false;
        while (1) {
            if (pA == pB && pA != nullptr) {
                return pA;
            }

            if (pA == nullptr) {
                if (jumpA) {
                    return nullptr;
                }
                pA = headB;
                jumpA = true;
            } else {
                pA = pA->next;
            }

            if (pB == nullptr) {
                if (jumpB) {
                    return nullptr;
                }
                pB = headA;
                jumpB = true;
            } else {
                pB = pB->next;
            }
        }
        return nullptr;
    }
};