补全数组与链表/链表（LinkedList）中C语言部分

docs/chapter_array_and_linkedlist/linked_list.md

@@ -97,7 +97,11 @@ comments: true
 === "C"
 
     ```c title=""
-
+    /* 链表结点结构体 */
+    typedef struct ListNode {
+        int val;                    // 结点值
+        struct ListNode *next;      // 指向下一结点的指针（引用）
+    }ListNode;
     ```
 
 === "C#"
@@ -226,7 +230,25 @@ comments: true
 === "C"
 
     ```c title=""
+    /* 初始化链表 1 -> 3 -> 2 -> 5 -> 4 */
+    // 初始化各个结点
+    ListNode* n0 = (ListNode*) malloc(sizeof(ListNode));
+    ListNode* n1 = (ListNode*) malloc(sizeof(ListNode));
+    ListNode* n2 = (ListNode*) malloc(sizeof(ListNode));
+    ListNode* n3 = (ListNode*) malloc(sizeof(ListNode));
+    ListNode* n4 = (ListNode*) malloc(sizeof(ListNode));
 
+    n0->val = 1;
+    n1->val = 3;
+    n2->val = 2;
+    n3->val = 5;
+    n4->val = 4;
+
+    // 构建引用指向
+    n0->next = n1;
+    n1->next = n2;
+    n2->next = n3;
+    n3->next = n4;
     ```
 
 === "C#"
@@ -384,7 +406,24 @@ comments: true
 === "C"
 
     ```c title=""
+    /* 在链表的结点 n0 之后插入结点 P */
+    void insert(ListNode* n0, ListNode* P) {
+        ListNode* n1 = n0->next;
+        n0->next = P;
+        P->next = n1;
+    }
 
+    /* 删除链表的结点 n0 之后的首个结点 */
+    void remove(ListNode* n0) {
+        if (n0->next == NULL)
+            return;
+        // n0 -> P -> n1
+        ListNode* P = n0->next;
+        ListNode* n1 = P->next;
+        n0->next = n1;
+        // 释放内存
+        free(P) ;
+}
     ```
 
 === "C#"
@@ -501,7 +540,15 @@ comments: true
 === "C"
 
     ```c title=""
-
+    /* 访问链表中索引为 index 的结点 */
+    ListNode* access(ListNode* head, int index) {
+        for (int i = 0; i < index; i++) {
+            head = head->next;
+            if (head == NULL)
+                return NULL;
+        }
+        return head;
+    }
     ```
 
 === "C#"
@@ -626,7 +673,17 @@ comments: true
 === "C"
 
     ```c title=""
-
+    /* 在链表中查找值为 target 的首个结点 */
+    int find(ListNode* head, int target) {
+        int index = 0;
+        while (head != NULL) {
+            if (head->val == target)
+                return index;
+            head = head->next;
+            index++;
+        }
+        return -1;
+    }
     ```
 
 === "C#"
@@ -745,7 +802,11 @@ comments: true
 === "C"
 
     ```c title=""
-
+    typedef struct ListNode {
+        int val;
+        struct ListNode *next;
+        struct ListNode *prev;
+    }ListNode;
     ```
 
 === "C#"