148:排序链表

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

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+//给你链表的头结点 head ，请将其按 升序 排列并返回 排序后的链表 。 
+//
+// 进阶： 
+//
+// 
+// 你可以在 O(n log n) 时间复杂度和常数级空间复杂度下，对链表进行排序吗？ 
+// 
+//
+// 
+//
+// 示例 1： 
+//
+// 
+//输入：head = [4,2,1,3]
+//输出：[1,2,3,4]
+// 
+//
+// 示例 2： 
+//
+// 
+//输入：head = [-1,5,3,4,0]
+//输出：[-1,0,3,4,5]
+// 
+//
+// 示例 3： 
+//
+// 
+//输入：head = []
+//输出：[]
+// 
+//
+// 
+//
+// 提示： 
+//
+// 
+// 链表中节点的数目在范围 [0, 5 * 104] 内 
+// -105 <= Node.val <= 105 
+// 
+// Related Topics 排序 链表 
+// 👍 1168 👎 0
+
+package leetcode.editor.cn;
+
+import com.code.leet.entiy.ListNode;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+
+//148:排序链表
+public class SortList{
+    public static void main(String[] args) {
+        //测试代码
+        Solution solution = new SortList().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 ListNode sortList(ListNode head) {
+        List<ListNode> list = new ArrayList<>();
+        while (head != null) {
+            list.add(head);
+            head = head.next;
+        }
+        Collections.sort(list, (n1, n2) -> n1.val - n2.val);
+        int size = list.size();
+        if (size == 0) {
+            return null;
+        }
+        head = list.get(0);
+        ListNode temp = head;
+        for (int i = 1; i < size; i++) {
+            temp.next = list.get(i);
+            temp.next.next = null;
+            temp = temp.next;
+        }
+
+        return head;
+    }
+}
+//leetcode submit region end(Prohibit modification and deletion)
+
+}

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

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+<p>给你链表的头结点 <code>head</code> ，请将其按 <strong>升序</strong> 排列并返回 <strong>排序后的链表</strong> 。</p>
+
+<p><b>进阶：</b></p>
+
+<ul>
+	<li>你可以在 <code>O(n log n)</code> 时间复杂度和常数级空间复杂度下，对链表进行排序吗？</li>
+</ul>
+
+<p> </p>
+
+<p><strong>示例 1：</strong></p>
+<img alt="" src="https://assets.leetcode.com/uploads/2020/09/14/sort_list_1.jpg" />
+<pre>
+<b>输入：</b>head = [4,2,1,3]
+<b>输出：</b>[1,2,3,4]
+</pre>
+
+<p><strong>示例 2：</strong></p>
+<img alt="" src="https://assets.leetcode.com/uploads/2020/09/14/sort_list_2.jpg" />
+<pre>
+<b>输入：</b>head = [-1,5,3,4,0]
+<b>输出：</b>[-1,0,3,4,5]
+</pre>
+
+<p><strong>示例 3：</strong></p>
+
+<pre>
+<b>输入：</b>head = []
+<b>输出：</b>[]
+</pre>
+
+<p> </p>
+
+<p><b>提示：</b></p>
+
+<ul>
+	<li>链表中节点的数目在范围 <code>[0, 5 * 10<sup>4</sup>]</code> 内</li>
+	<li><code>-10<sup>5</sup> <= Node.val <= 10<sup>5</sup></code></li>
+</ul>
+<div><div>Related Topics</div><div><li>排序</li><li>链表</li></div></div>\n<div><li>👍 1168</li><li>👎 0</li></div>