Merge pull request krahets#244 from Gonglja/master

Add linked_list.c

codes/c/chapter_array_and_linkedlist/CMakeLists.txt

@@ -1 +1,2 @@
-add_executable(array array.c)
+add_executable(array array.c)
+add_executable(linked_list linked_list.c)

codes/c/chapter_array_and_linkedlist/linked_list.c

@@ -0,0 +1,88 @@
+/**
+ * File: linked_list.c
+ * Created Time: 2022-01-12
+ * Author: Zero ([email protected])
+ */
+
+#include "../include/include.h"
+
+/* 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 */
+// 由于引入了 stdio.h ，此处无法使用 remove 关键词
+// 详见 https://github.com/krahets/hello-algo/pull/244#discussion_r1067863888
+void removeNode(ListNode* n0) {
+    if (!n0->next)
+        return;
+    // n0 -> P -> n1
+    ListNode *P = n0->next;
+    ListNode *n1 = P->next;
+    n0->next = n1;
+    // 释放内存
+    free(P);
+}
+
+/* 访问链表中索引为 index 的结点 */
+ListNode* access(ListNode* head, int index) {
+    while (head && head->next && index) {
+        head = head->next;
+        index--;
+    }
+    return head;
+}
+
+/* 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) {
+        if (head->val == target)
+            return index;
+        head = head->next;
+        index++;
+    }
+    return -1;
+}
+
+
+/* Driver Code */
+int main() {
+    /* 初始化链表 */
+    // 初始化各个结点 
+    ListNode* n0 = newListNode(1);
+    ListNode* n1 = newListNode(3);
+    ListNode* n2 = newListNode(2);
+    ListNode* n3 = newListNode(5);
+    ListNode* n4 = newListNode(4);
+    // 构建引用指向
+    n0->next = n1;
+    n1->next = n2;
+    n2->next = n3;
+    n3->next = n4;
+    printf("初始化的链表为\r\n"); 
+    printLinkedList(n0);
+
+    /* 插入结点 */
+    insert(n0, newListNode(0));
+    printf("插入结点后的链表为\r\n");
+    printLinkedList(n0);
+
+    /* 删除结点 */
+    removeNode(n0);
+    printf("删除结点后的链表为\r\n");
+    printLinkedList(n0);
+
+    /* 访问结点 */
+    ListNode* node = access(n0, 3);
+    printf("链表中索引 3 处的结点的值 = %d\r\n", node->val);
+
+    /* 查找结点 */
+    int index = find(n0, 2);
+    printf("链表中值为 2 的结点的索引 = %d\r\n", index);
+
+    return 0;
+}