feat(leecode): 23.合并k个升序链表

docs/10.LeeCode/23.合并k个升序链表.md

@@ -73,4 +73,6 @@ Langs: c cpp csharp golang java javascript kotlin php python python3 ruby rust s
 	<li><code>lists[i].length</code> 的总和不超过 <code>10^4</code></li>
 </ul>
 
-<<< @/src/LeeCode/23.合并k个升序链表.js
+<<< @/src/LeeCode/23.合并k个升序链表.js
+<<< @/src/LeeCode/23.合并k个升序链表1.js
+<<< @/src/LeeCode/23.合并k个升序链表2.js

src/LeeCode/23.合并k个升序链表.js

@@ -1,7 +1,8 @@
 /*
  * @lc app=leetcode.cn id=23 lang=javascript
  *
- * [23] 合并K个升序链表
+ * [23] 合并 K 个升序链表
+ * 递归
  */
 
 // @lc code=start
@@ -17,29 +18,27 @@
  * @return {ListNode}
  */
 var mergeKLists = function (lists) {
-    if (lists.length < 1) return null;
-    if (lists.length === 1) return lists[0];
+  if (lists.length === 0) {
+    return null
+  }
 
-    const hair = new ListNode(0, lists.shift());
-    let p = hair, q, r;
-    while (lists.length) {
-        q = lists.shift();
-        while (q) {
-            if (p.next === null) {
-                p.next = q;
-                break;
-            } else if (q.val <= p.next.val) {
-                r = q.next;
-                q.next = p.next;
-                p.next = q;
-                q = r;
-            } else {
-                p = p.next;
-            }
-        }
-        p = hair;
+  return lists.reduce((acc, item) => {
+    const dummy = new ListNode()
+    let p = dummy
+    let l1 = acc
+    let l2 = item
+    while (l1 && l2) {
+      if (l1.val <= l2.val) {
+        p.next = l1
+        l1 = l1.next
+      } else {
+        p.next = l2
+        l2 = l2.next
+      }
+      p = p.next
     }
-    return hair.next
-};
+    p.next = l1 ? l1 : l2
+    return dummy.next
+  })
+}
 // @lc code=end
-

src/LeeCode/23.合并k个升序链表1.js

@@ -0,0 +1,46 @@
+/*
+ * @lc app=leetcode.cn id=23 lang=javascript
+ *
+ * [23] 合并K个升序链表
+ * 非递归
+ */
+
+// @lc code=start
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val, next) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.next = (next===undefined ? null : next)
+ * }
+ */
+/**
+ * @param {ListNode[]} lists
+ * @return {ListNode}
+ */
+var mergeKLists = function (lists) {
+    if (lists.length < 1) return null;
+    if (lists.length === 1) return lists[0];
+
+    const hair = new ListNode(0, lists.shift());
+    let p = hair, q, r;
+    while (lists.length) {
+        q = lists.shift();
+        while (q) {
+            if (p.next === null) {
+                p.next = q;
+                break;
+            } else if (q.val <= p.next.val) {
+                r = q.next;
+                q.next = p.next;
+                p.next = q;
+                q = r;
+            } else {
+                p = p.next;
+            }
+        }
+        p = hair;
+    }
+    return hair.next
+};
+// @lc code=end
+

src/LeeCode/23.合并k个升序链表2.js

@@ -0,0 +1,45 @@
+/*
+ * @lc app=leetcode.cn id=23 lang=javascript
+ *
+ * [23] 合并 K 个升序链表
+ * 非递归
+ */
+
+// @lc code=start
+/**
+ * Definition for singly-linked list.
+ * function ListNode(val, next) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.next = (next===undefined ? null : next)
+ * }
+ */
+/**
+ * @param {ListNode[]} lists
+ * @return {ListNode}
+ */
+var mergeKLists = function (lists) {
+    if (lists.length === 0) {
+      return null
+    }
+
+    return lists.reduce((acc, item) => {
+      const dummy = new ListNode()
+      let p = dummy
+      let l1 = acc
+      let l2 = item
+      while (l1 && l2) {
+        if (l1.val <= l2.val) {
+          p.next = l1
+          l1 = l1.next
+        } else {
+          p.next = l2
+          l2 = l2.next
+        }
+        p = p.next
+      }
+      p.next = l1 ? l1 : l2
+      return dummy.next
+    })
+  }
+  // @lc code=end
+