Add the chapter of searching.
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@ -35,9 +35,10 @@ For full documentation visit [mkdocs.org](https://www.mkdocs.org).
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| 更新:二叉搜索树 | 2022-11-14 |
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| 更新:首页介绍 | 2022-11-15 |
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| 更新:关于本书</br>新增:如何使用本书</br>新增:一起参与创作 | 2022-11-16 |
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| 新增:查找算法 | 2022-11-19 |
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## License
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![cc_by-nc-sa](https://i.creativecommons.org/l/by-nc-sa/4.0/88x31.png)
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The **texts, codes, images, photos, and videos** present on the website(book) is licensed under a [CC BY-NC-SA-4.0](https://creativecommons.org/licenses/by-nc-sa/4.0/).
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The **texts, codes, images, photos, and videos** present on this work is licensed under [CC BY-NC-SA-4.0](https://creativecommons.org/licenses/by-nc-sa/4.0/).
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52
codes/java/chapter_searching/binary_search.java
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52
codes/java/chapter_searching/binary_search.java
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package chapter_searching;
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public class binary_search {
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/* 二分查找(双闭区间) */
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static int binarySearch(int[] nums, int target) {
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// 初始化双闭区间 [0, n-1] ,即 i, j 分别指向数组首元素、尾元素
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int i = 0, j = nums.length - 1;
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// 循环,当搜索区间为空时跳出(当 i > j 时为空)
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while (i <= j) {
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int m = (i + j) / 2; // 计算中点索引 m
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if (nums[m] < target) // 此情况说明 target 在区间 [m+1, j] 中
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i = m + 1;
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else if (nums[m] > target) // 此情况说明 target 在区间 [i, m-1] 中
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j = m - 1;
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else // 找到目标元素,返回其索引
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return m;
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}
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// 未找到目标元素,返回 -1
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return -1;
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}
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/* 二分查找(左闭右开) */
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static int binarySearch1(int[] nums, int target) {
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// 初始化左闭右开 [0, n) ,即 i, j 分别指向数组首元素、尾元素+1
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int i = 0, j = nums.length;
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// 循环,当搜索区间为空时跳出(当 i = j 时为空)
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while (i < j) {
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int m = (i + j) / 2; // 计算中点索引 m
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if (nums[m] < target) // 此情况说明 target 在区间 [m+1, j) 中
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i = m + 1;
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else if (nums[m] > target) // 此情况说明 target 在区间 [i, m) 中
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j = m;
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else // 找到目标元素,返回其索引
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return m;
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}
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// 未找到目标元素,返回 -1
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return -1;
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}
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public static void main(String[] args) {
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int target = 6;
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int[] nums = { 1, 3, 6, 8, 12, 15, 23, 67, 70, 92 };
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/* 二分查找(双闭区间) */
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int index = binarySearch(nums, target);
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System.out.println("目标元素 6 的索引 = " + index);
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/* 二分查找(左闭右开) */
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index = binarySearch1(nums, target);
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System.out.println("目标元素 6 的索引 = " + index);
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}
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}
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codes/java/chapter_searching/hashing_search.java
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codes/java/chapter_searching/hashing_search.java
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package chapter_searching;
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import include.*;
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import java.util.*;
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public class hashing_search {
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/* 哈希查找(数组) */
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static int hashingSearch(Map<Integer, Integer> map, int target) {
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// 哈希表的 key: 目标元素,value: 索引
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// 若哈希表中无此 key ,返回 -1
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return map.getOrDefault(target, -1);
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}
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/* 哈希查找(链表) */
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static ListNode hashingSearch1(Map<Integer, ListNode> map, int target) {
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// 哈希表的 key: 目标结点值,value: 结点对象
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// 若哈希表中无此 key ,返回 -1
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return map.getOrDefault(target, null);
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}
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public static void main(String[] args) {
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int target = 3;
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/* 哈希查找(数组) */
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int[] nums = { 1, 5, 3, 2, 4, 7, 5, 9, 10, 8 };
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// 初始化哈希表
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Map<Integer, Integer> map = new HashMap<>();
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for (int i = 0; i < nums.length; i++) {
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map.put(nums[i], i); // key: 元素,value: 索引
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}
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int index = hashingSearch(map, target);
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System.out.println("目标元素 3 的索引 = " + index);
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/* 哈希查找(链表) */
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ListNode head = ListNode.arrToLinkedList(nums);
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// 初始化哈希表
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Map<Integer, ListNode> map1 = new HashMap<>();
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while (head != null) {
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map1.put(head.val, head); // key: 结点值,value: 结点
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head = head.next;
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}
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ListNode node = hashingSearch1(map1, target);
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System.out.println("目标结点值 3 的对应结点对象为 " + node);
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}
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}
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codes/java/chapter_searching/linear_search.java
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codes/java/chapter_searching/linear_search.java
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package chapter_searching;
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import include.*;
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public class linear_search {
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/* 线性查找(数组) */
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static int linearSearch(int[] nums, int target) {
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// 遍历数组
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for (int i = 0; i < nums.length; i++) {
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// 找到目标元素,返回其索引
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if (nums[i] == target)
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return i;
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}
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// 未找到目标元素,返回 -1
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return -1;
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}
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/* 线性查找(链表) */
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static ListNode linearSearch(ListNode head, int target) {
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// 遍历链表
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while (head != null) {
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// 找到目标结点,返回之
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if (head.val == target)
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return head;
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head = head.next;
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}
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// 未找到目标结点,返回 null
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return null;
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}
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public static void main(String[] args) {
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int target = 3;
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/* 在数组中执行线性查找 */
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int[] nums = { 1, 5, 3, 2, 4, 7, 5, 9, 10, 8 };
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int index = linearSearch(nums, target);
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System.out.println("目标元素 3 的索引 = " + index);
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/* 在链表中执行线性查找 */
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ListNode head = ListNode.arrToLinkedList(nums);
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ListNode node = linearSearch(head, target);
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System.out.println("目标结点值 3 的对应结点对象为 " + node);
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}
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}
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19
mkdocs.yml
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mkdocs.yml
@ -113,19 +113,19 @@ extra_css:
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# Page tree
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nav:
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- 关于本书:
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- chapter_about/index.md
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- 如何使用本书: chapter_about/how_to_read.md
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- 编程环境安装: chapter_about/installation.md
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- 一起参与创作: chapter_about/contribution.md
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- License: chapter_about/license.md
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- 算法无处不在:
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- 前言:
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- chapter_introduction/index.md
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- 如何使用本书:
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- 算法学习建议: chapter_prerequisites/suggestions.md
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- 编程环境安装: chapter_prerequisites/installation.md
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- 一起参与创作: chapter_prerequisites/contribution.md
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- 算法是什么:
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- chapter_dsa_introduction/index.md
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- 计算复杂度:
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- 算法效率评估: chapter_computational_complexity/performance_evaluation.md
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- 时间复杂度: chapter_computational_complexity/time_complexity.md
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- 空间复杂度: chapter_computational_complexity/space_complexity.md
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- 权衡时间与空间: chapter_computational_complexity/space_time_tradeoff.md
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- 权衡时间与空间 *: chapter_computational_complexity/space_time_tradeoff.md
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- 小结: chapter_computational_complexity/summary.md
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- 数据结构简介:
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- 数据与内存: chapter_data_structure/data_and_memory.md
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@ -134,7 +134,7 @@ nav:
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- 数组与链表:
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- 数组(Array): chapter_array_and_linkedlist/array.md
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- 链表(LinkedList): chapter_array_and_linkedlist/linked_list.md
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- 列表(List): chapter_array_and_linkedlist/list.md
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- 列表(List)*: chapter_array_and_linkedlist/list.md
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- 小结: chapter_array_and_linkedlist/summary.md
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- 栈与队列:
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- 栈(Stack): chapter_stack_and_queue/stack.md
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@ -149,6 +149,7 @@ nav:
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- 查找算法:
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- 线性查找: chapter_searching/linear_search.md
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- 二分查找: chapter_searching/binary_search.md
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- 哈希查找: chapter_searching/hashing_search.md
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- 小结: chapter_searching/summary.md
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- 参考文献:
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- chapter_reference/index.md
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