Update 链表相关.md

blogs/Algorithm/剑指 Offer/链表相关.md

@@ -222,3 +222,45 @@ class Solution {
 }
 ```
 
+[52. 两个链表的第一个公共节点](https://leetcode-cn.com/problems/liang-ge-lian-biao-de-di-yi-ge-gong-gong-jie-dian-lcof/)
+
+```java
+public class Solution {
+    public ListNode getIntersectionNode(ListNode headA, ListNode headB) {
+        ListNode h1 = headA;
+        ListNode h2 = headB;
+        while (h1 != null && h2 != null) {
+            if (h1 == h2) {
+                return h1;
+            }
+            h1 = h1.next;
+            h2 = h2.next;
+            if (h1 == null && h2 == null) {
+                return null;
+            }
+            if (h1 == null) {
+                h1 = headB;
+            }
+            if (h2 == null) {
+                h2 = headA;
+            }
+        }
+        return null;
+    }
+}
+```
+
+```java
+public class Solution {
+    public ListNode getIntersectionNode(ListNode headA, ListNode headB) {
+        ListNode h1 = headA;
+        ListNode h2 = headB;
+        while (h1 != h2) {
+            h1 = h1 == null ? headB : h1.next;
+            h2 = h2 == null ? headA : h2.next;
+        }
+        return h1;
+    }
+}
+```
+