BM2 链表内指定区间反转

bm/src/main/java/com/huangge1199/nowcoder/bm/BM2/Solution.java

@@ -0,0 +1,40 @@
+package com.huangge1199.nowcoder.bm.BM2;
+
+import com.huangge1199.nowcoder.common.ListNode;
+
+/**
+ * @author hyy
+ * @Classname Solution
+ * @Description BM2 链表内指定区间反转
+ * @Date 2022/7/26 15:57
+ */
+public class Solution {
+    /**
+     *
+     * @param head ListNode类
+     * @param m int整型
+     * @param n int整型
+     * @return ListNode类
+     */
+    public ListNode reverseBetween (ListNode head, int m, int n) {
+        // write code here
+        ListNode cur = head;
+        ListNode bef = new ListNode(0);
+        bef.next = head;
+        ListNode pre = bef;
+        int index = 1;
+        while (index < n) {
+            if (index < m) {
+                pre = cur;
+                cur = cur.next;
+            } else {
+                ListNode tmp = cur.next;
+                cur.next = tmp.next;
+                tmp.next = pre.next;
+                pre.next = tmp;
+            }
+            index++;
+        }
+        return bef.next;
+    }
+}

common/src/main/java/com/huangge1199/nowcoder/common/ListNode.java

@@ -13,7 +13,7 @@ public class ListNode {
     public int val;
     public ListNode next = null;
 
-    ListNode(int val) {
+    public ListNode(int val) {
         this.val = val;
     }
 }