143:重排链表

src/main/java/leetcode/editor/cn/ReorderList.java

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+//给定一个单链表 L：L0→L1→…→Ln-1→Ln ， 
+//将其重新排列后变为： L0→Ln→L1→Ln-1→L2→Ln-2→… 
+//
+// 你不能只是单纯的改变节点内部的值，而是需要实际的进行节点交换。 
+//
+// 示例 1: 
+//
+// 给定链表 1->2->3->4, 重新排列为 1->4->2->3. 
+//
+// 示例 2: 
+//
+// 给定链表 1->2->3->4->5, 重新排列为 1->5->2->4->3. 
+// Related Topics 链表 
+// 👍 593 👎 0
+
+package leetcode.editor.cn;
+
+import com.code.leet.entiy.ListNode;
+
+import java.util.ArrayList;
+import java.util.List;
+
+//143:重排链表
+public class ReorderList{
+    public static void main(String[] args) {
+        //测试代码
+        Solution solution = new ReorderList().new Solution();
+    }
+    //力扣代码
+    //leetcode submit region begin(Prohibit modification and deletion)
+/**
+ * Definition for singly-linked list.
+ * public class ListNode {
+ *     int val;
+ *     ListNode next;
+ *     ListNode() {}
+ *     ListNode(int val) { this.val = val; }
+ *     ListNode(int val, ListNode next) { this.val = val; this.next = next; }
+ * }
+ */
+class Solution {
+    public void reorderList(ListNode head) {
+        if (head == null) {
+            return;
+        }
+        List<ListNode> list = new ArrayList<>();
+        ListNode temp = head.next;
+        while (temp != null) {
+            list.add(temp);
+            temp = temp.next;
+        }
+        temp = head;
+        int size = list.size();
+        int count = (size + 1) / 2;
+        for (int i = 1; i <= count; i++) {
+            if (size - i != i - 1) {
+                temp.next = list.get(size - i);
+                temp.next.next = list.get(i - 1);
+                temp = temp.next.next;
+            } else {
+                temp.next = list.get(i - 1);
+                temp = temp.next;
+            }
+        }
+        temp.next = null;
+    }
+}
+//leetcode submit region end(Prohibit modification and deletion)
+
+}

src/main/java/leetcode/editor/cn/ReorderList.md

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+<p>给定一个单链表&nbsp;<em>L</em>：<em>L</em><sub>0</sub>&rarr;<em>L</em><sub>1</sub>&rarr;&hellip;&rarr;<em>L</em><sub><em>n</em>-1</sub>&rarr;<em>L</em><sub>n ，</sub><br>
+将其重新排列后变为： <em>L</em><sub>0</sub>&rarr;<em>L</em><sub><em>n</em></sub>&rarr;<em>L</em><sub>1</sub>&rarr;<em>L</em><sub><em>n</em>-1</sub>&rarr;<em>L</em><sub>2</sub>&rarr;<em>L</em><sub><em>n</em>-2</sub>&rarr;&hellip;</p>
+
+<p>你不能只是单纯的改变节点内部的值，而是需要实际的进行节点交换。</p>
+
+<p><strong>示例&nbsp;1:</strong></p>
+
+<pre>给定链表 1-&gt;2-&gt;3-&gt;4, 重新排列为 1-&gt;4-&gt;2-&gt;3.</pre>
+
+<p><strong>示例 2:</strong></p>
+
+<pre>给定链表 1-&gt;2-&gt;3-&gt;4-&gt;5, 重新排列为 1-&gt;5-&gt;2-&gt;4-&gt;3.</pre>
+<div><div>Related Topics</div><div><li>链表</li></div></div>\n<div><li>👍 593</li><li>👎 0</li></div>