41 lines
1.2 KiB
Java
41 lines
1.2 KiB
Java
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package linkedlist;
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import java.util.HashSet;
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/**
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* 题目：160. 相交链表 (getIntersectionNode)
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* 描述：给你两个单链表的头节点 headA 和 headB ，请你找出并返回两个单链表相交的起始节点。如果两个链表不存在相交节点，返回 null 。
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* 链接：https://leetcode.cn/problems/intersection-of-two-linked-lists/
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*/
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//没想出高效方法
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public class GetIntersectionNode {
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public ListNode getIntersectionNode(ListNode headA, ListNode headB) {
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HashSet<ListNode> visited = new HashSet<ListNode>();
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ListNode temp = headA;
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while (temp != null) {
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visited.add(temp);
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temp = temp.next;
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}
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temp = headB;
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while (temp != null) {
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if (visited.contains(temp)) {
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return temp;
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}
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temp = temp.next;
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}
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return null;
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}
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//高效方法
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public ListNode getIntersectionNode1(ListNode headA, ListNode headB) {
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ListNode A = headA, B = headB;
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while (A != B) {
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A = A != null ? A.next : headB;
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B = B != null ? B.next : headA;
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}
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return A;
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}
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}
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