Feat: 1669

FX-Max · FX-Max · commit da7eded9b12f · 2021-10-24T23:27:33.000+08:00
diff --git a/problems/1669-merge-in-between-linked-lists.md b/problems/1669-merge-in-between-linked-lists.md
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+## 题目
+
+* 1669. 合并两个链表
+
+给你两个链表 list1 和 list2 ，它们包含的元素分别为 n 个和 m 个。
+
+请你将 list1 中下标从 a 到 b 的全部节点都删除，并将list2 接在被删除节点的位置。
+
+## 思路
+
+
+## 代码
+
+```php
+
+class Solution {
+
+    /**
+     * @param ListNode $list1
+     * @param Integer $a
+     * @param Integer $b
+     * @param ListNode $list2
+     * @return ListNode
+     */
+    function mergeInBetween($list1, $a, $b, $list2) {
+        $n = 1;
+        $left = $list1;
+        $right = $list1;
+        $dumyRight = null;
+        $dumyRight->next = $right;
+        while ($n <= $b) {
+            $dumyRight->next = $right->next->next;
+            if ($n < $a) {
+                $left = $left->next; 
+            }
+            $right = $right->next;
+            
+            $n++;
+        }
+        $left->next = $list2;
+        $cur = $list2;
+        while ($cur->next) {
+            $cur = $cur->next;
+        }
+        $cur->next = $dumyRight->next;
+        return $list1;
+    }
+}
+
+```
