diff --git a/chapter_computational_complexity/iteration_and_recursion.md b/chapter_computational_complexity/iteration_and_recursion.md
index 34c9373bc..f39c35dd7 100644
--- a/chapter_computational_complexity/iteration_and_recursion.md
+++ b/chapter_computational_complexity/iteration_and_recursion.md
@@ -1568,7 +1568,24 @@ status: new
 === "Dart"
 
     ```dart title="recursion.dart"
-    [class]{}-[func]{forLoopRecur}
+    /* 使用迭代模拟递归 */
+    int forLoopRecur(int n) {
+      // 使用一个显式的栈来模拟系统调用栈
+      List<int> stack = [];
+      int res = 0;
+      // 递：递归调用
+      for (int i = n; i > 0; i--) {
+        // 通过“入栈操作”模拟“递”
+        stack.add(i);
+      }
+      // 归：返回结果
+      while (!stack.isEmpty) {
+        // 通过“出栈操作”模拟“归”
+        res += stack.removeLast();
+      }
+      // res = 1+2+3+...+n
+      return res;
+    }
     ```
 
 === "Rust"
diff --git a/chapter_dynamic_programming/intro_to_dynamic_programming.md b/chapter_dynamic_programming/intro_to_dynamic_programming.md
index 2f821e77c..4ddef50b7 100644
--- a/chapter_dynamic_programming/intro_to_dynamic_programming.md
+++ b/chapter_dynamic_programming/intro_to_dynamic_programming.md
@@ -321,9 +321,35 @@ comments: true
 === "C"
 
     ```c title="climbing_stairs_backtrack.c"
-    [class]{}-[func]{backtrack}
+    /* 回溯 */
+    void backtrack(int *choices, int state, int n, int *res, int len) {
+        // 当爬到第 n 阶时，方案数量加 1
+        if (state == n)
+            res[0]++;
+        // 遍历所有选择
+        for (int i = 0; i < len; i++) {
+            int choice = choices[i];
+            // 剪枝：不允许越过第 n 阶
+            if (state + choice > n)
+                break;
+            // 尝试：做出选择，更新状态
+            backtrack(choices, state + choice, n, res, len);
+            // 回退
+        }
+    }
 
-    [class]{}-[func]{climbingStairsBacktrack}
+    /* 爬楼梯：回溯 */
+    int climbingStairsBacktrack(int n) {
+        int choices[2] = {1, 2}; // 可选择向上爬 1 或 2 阶
+        int state = 0;           // 从第 0 阶开始爬
+        int *res = (int *)malloc(sizeof(int));
+        *res = 0;                // 使用 res[0] 记录方案数量
+        int len = sizeof(choices) / sizeof(int);
+        backtrack(choices, state, n, res, len);
+        int result = *res;
+        free(res);
+        return result;
+    }
     ```
 
 === "Zig"
@@ -576,9 +602,20 @@ $$
 === "C"
 
     ```c title="climbing_stairs_dfs.c"
-    [class]{}-[func]{dfs}
+    /* 搜索 */
+    int dfs(int i) {
+        // 已知 dp[1] 和 dp[2] ，返回之
+        if (i == 1 || i == 2)
+            return i;
+        // dp[i] = dp[i-1] + dp[i-2]
+        int count = dfs(i - 1) + dfs(i - 2);
+        return count;
+    }
 
-    [class]{}-[func]{climbingStairsDFS}
+    /* 爬楼梯：搜索 */
+    int climbingStairsDFS(int n) {
+        return dfs(n);
+    }
     ```
 
 === "Zig"
@@ -880,9 +917,32 @@ $$
 === "C"
 
     ```c title="climbing_stairs_dfs_mem.c"
-    [class]{}-[func]{dfs}
+    /* 记忆化搜索 */
+    int dfs(int i, int *mem) {
+        // 已知 dp[1] 和 dp[2] ，返回之
+        if (i == 1 || i == 2)
+            return i;
+        // 若存在记录 dp[i] ，则直接返回之
+        if (mem[i] != -1)
+            return mem[i];
+        // dp[i] = dp[i-1] + dp[i-2]
+        int count = dfs(i - 1, mem) + dfs(i - 2, mem);
+        // 记录 dp[i]
+        mem[i] = count;
+        return count;
+    }
 
-    [class]{}-[func]{climbingStairsDFSMem}
+    /* 爬楼梯：记忆化搜索 */
+    int climbingStairsDFSMem(int n) {
+        // mem[i] 记录爬到第 i 阶的方案总数，-1 代表无记录
+        int *mem = (int *)malloc((n + 1) * sizeof(int));
+        for (int i = 0; i <= n; i++) {
+            mem[i] = -1;
+        }
+        int result = dfs(n, mem);
+        free(mem);
+        return result;
+    }
     ```
 
 === "Zig"
@@ -1126,7 +1186,23 @@ $$
 === "C"
 
     ```c title="climbing_stairs_dp.c"
-    [class]{}-[func]{climbingStairsDP}
+    /* 爬楼梯：动态规划 */
+    int climbingStairsDP(int n) {
+        if (n == 1 || n == 2)
+            return n;
+        // 初始化 dp 表，用于存储子问题的解
+        int *dp = (int *)malloc((n + 1) * sizeof(int));
+        // 初始状态：预设最小子问题的解
+        dp[1] = 1;
+        dp[2] = 2;
+        // 状态转移：从较小子问题逐步求解较大子问题
+        for (int i = 3; i <= n; i++) {
+            dp[i] = dp[i - 1] + dp[i - 2];
+        }
+        int result = dp[n];
+        free(dp);
+        return result;
+    }
     ```
 
 === "Zig"
@@ -1336,7 +1412,18 @@ $$
 === "C"
 
     ```c title="climbing_stairs_dp.c"
-    [class]{}-[func]{climbingStairsDPComp}
+    /* 爬楼梯：空间优化后的动态规划 */
+    int climbingStairsDPComp(int n) {
+        if (n == 1 || n == 2)
+            return n;
+        int a = 1, b = 2;
+        for (int i = 3; i <= n; i++) {
+            int tmp = b;
+            b = a + b;
+            a = tmp;
+        }
+        return b;
+    }
     ```
 
 === "Zig"
diff --git a/chapter_graph/graph_traversal.md b/chapter_graph/graph_traversal.md
index 0b1fbf543..0d30b114d 100644
--- a/chapter_graph/graph_traversal.md
+++ b/chapter_graph/graph_traversal.md
@@ -6,7 +6,7 @@ comments: true
 
 树代表的是“一对多”的关系，而图则具有更高的自由度，可以表示任意的“多对多”关系。因此，我们可以把树看作是图的一种特例。显然，**树的遍历操作也是图的遍历操作的一种特例**。
 
-图和树都都需要应用搜索算法来实现遍历操作。图的遍历方式可分为两种：「广度优先遍历 breadth-first traversal」和「深度优先遍历 depth-first traversal」。它们也常被称为「广度优先搜索 breadth-first search」和「深度优先搜索 depth-first search」，简称 BFS 和 DFS 。
+图和树都需要应用搜索算法来实现遍历操作。图的遍历方式可分为两种：「广度优先遍历 breadth-first traversal」和「深度优先遍历 depth-first traversal」。它们也常被称为「广度优先搜索 breadth-first search」和「深度优先搜索 depth-first search」，简称 BFS 和 DFS 。
 
 ## 9.3.1 &nbsp; 广度优先遍历
 
diff --git a/chapter_hashing/hash_collision.md b/chapter_hashing/hash_collision.md
index 3af6ba4d7..5e57a1133 100644
--- a/chapter_hashing/hash_collision.md
+++ b/chapter_hashing/hash_collision.md
@@ -2392,20 +2392,16 @@ comments: true
     /* 开放寻址哈希表 */
     class HashMapOpenAddressing {
       late int _size; // 键值对数量
-      late int _capacity; // 哈希表容量
-      late double _loadThres; // 触发扩容的负载因子阈值
-      late int _extendRatio; // 扩容倍数
+      int _capacity = 4; // 哈希表容量
+      double _loadThres = 2.0 / 3.0; // 触发扩容的负载因子阈值
+      int _extendRatio = 2; // 扩容倍数
       late List<Pair?> _buckets; // 桶数组
-      late Pair _removed; // 删除标记
+      Pair _TOMBSTONE = Pair(-1, "-1"); // 删除标记
 
       /* 构造方法 */
       HashMapOpenAddressing() {
         _size = 0;
-        _capacity = 4;
-        _loadThres = 2.0 / 3.0;
-        _extendRatio = 2;
         _buckets = List.generate(_capacity, (index) => null);
-        _removed = Pair(-1, "-1");
       }
 
       /* 哈希函数 */
@@ -2418,19 +2414,42 @@ comments: true
         return _size / _capacity;
       }
 
+      /* 搜索 key 对应的桶索引 */
+      int findBucket(int key) {
+        int index = hashFunc(key);
+        int firstTombstone = -1;
+        // 线性探测，当遇到空桶时跳出
+        while (_buckets[index] != null) {
+          // 若遇到 key ，返回对应桶索引
+          if (_buckets[index]!.key == key) {
+            // 若之前遇到了删除标记，则将键值对移动至该索引
+            if (firstTombstone != -1) {
+              _buckets[firstTombstone] = _buckets[index];
+              _buckets[index] = _TOMBSTONE;
+              return firstTombstone; // 返回移动后的桶索引
+            }
+            return index; // 返回桶索引
+          }
+          // 记录遇到的首个删除标记
+          if (firstTombstone == -1 && _buckets[index] == _TOMBSTONE) {
+            firstTombstone = index;
+          }
+          // 计算桶索引，越过尾部返回头部
+          index = (index + 1) % _capacity;
+        }
+        // 若 key 不存在，则返回添加点的索引
+        return firstTombstone == -1 ? index : firstTombstone;
+      }
+
       /* 查询操作 */
       String? get(int key) {
-        int index = hashFunc(key);
-        // 线性探测，从 index 开始向后遍历
-        for (int i = 0; i < _capacity; i++) {
-          // 计算桶索引，越过尾部返回头部
-          int j = (index + i) % _capacity;
-          // 若遇到空桶，说明无此 key ，则返回 null
-          if (_buckets[j] == null) return null;
-          // 若遇到指定 key ，则返回对应 val
-          if (_buckets[j]!.key == key && _buckets[j] != _removed)
-            return _buckets[j]!.val;
+        // 搜索 key 对应的桶索引
+        int index = findBucket(key);
+        // 若找到键值对，则返回对应 val
+        if (_buckets[index] != null && _buckets[index] != _TOMBSTONE) {
+          return _buckets[index]!.val;
         }
+        // 若键值对不存在，则返回 null
         return null;
       }
 
@@ -2440,42 +2459,26 @@ comments: true
         if (loadFactor() > _loadThres) {
           extend();
         }
-        int index = hashFunc(key);
-        // 线性探测，从 index 开始向后遍历
-        for (int i = 0; i < _capacity; i++) {
-          // 计算桶索引，越过尾部返回头部
-          int j = (index + i) % _capacity;
-          // 若遇到空桶、或带有删除标记的桶，则将键值对放入该桶
-          if (_buckets[j] == null || _buckets[j] == _removed) {
-            _buckets[j] = new Pair(key, val);
-            _size += 1;
-            return;
-          }
-          // 若遇到指定 key ，则更新对应 val
-          if (_buckets[j]!.key == key) {
-            _buckets[j]!.val = val;
-            return;
-          }
+        // 搜索 key 对应的桶索引
+        int index = findBucket(key);
+        // 若找到键值对，则覆盖 val 并返回
+        if (_buckets[index] != null && _buckets[index] != _TOMBSTONE) {
+          _buckets[index]!.val = val;
+          return;
         }
+        // 若键值对不存在，则添加该键值对
+        _buckets[index] = new Pair(key, val);
+        _size++;
       }
 
       /* 删除操作 */
       void remove(int key) {
-        int index = hashFunc(key);
-        // 线性探测，从 index 开始向后遍历
-        for (int i = 0; i < _capacity; i++) {
-          // 计算桶索引，越过尾部返回头部
-          int j = (index + i) % _capacity;
-          // 若遇到空桶，说明无此 key ，则直接返回
-          if (_buckets[j] == null) {
-            return;
-          }
-          // 若遇到指定 key ，则标记删除并返回
-          if (_buckets[j]!.key == key) {
-            _buckets[j] = _removed;
-            _size -= 1;
-            return;
-          }
+        // 搜索 key 对应的桶索引
+        int index = findBucket(key);
+        // 若找到键值对，则用删除标记覆盖它
+        if (_buckets[index] != null && _buckets[index] != _TOMBSTONE) {
+          _buckets[index] = _TOMBSTONE;
+          _size--;
         }
       }
 
@@ -2489,7 +2492,7 @@ comments: true
         _size = 0;
         // 将键值对从原哈希表搬运至新哈希表
         for (Pair? pair in bucketsTmp) {
-          if (pair != null && pair != _removed) {
+          if (pair != null && pair != _TOMBSTONE) {
             put(pair.key, pair.val);
           }
         }
@@ -2498,10 +2501,12 @@ comments: true
       /* 打印哈希表 */
       void printHashMap() {
         for (Pair? pair in _buckets) {
-          if (pair != null) {
-            print("${pair.key} -> ${pair.val}");
+          if (pair == null) {
+            print("null");
+          } else if (pair == _TOMBSTONE) {
+            print("TOMBSTONE");
           } else {
-            print(null);
+            print("${pair.key} -> ${pair.val}");
           }
         }
       }
diff --git a/chapter_hashing/hash_map.md b/chapter_hashing/hash_map.md
index ffd5c87b4..f96faae5c 100755
--- a/chapter_hashing/hash_map.md
+++ b/chapter_hashing/hash_map.md
@@ -309,12 +309,12 @@ comments: true
         cout << kv.first << " -> " << kv.second << endl;
     }
     // 单独遍历键 key
-    for (auto key: map) {
-        cout << key.first << endl;
+    for (auto kv: map) {
+        cout << kv.first << endl;
     }
     // 单独遍历值 value
-    for (auto val: map) {
-        cout << val.second << endl;
+    for (auto kv: map) {
+        cout << kv.second << endl;
     }
     ```
 
@@ -1408,7 +1408,126 @@ index = hash(key) % capacity
 
     typedef struct pair pair;
 
-    [class]{arrayHashMap}-[func]{}
+    /* 基于数组简易实现的哈希表 */
+    struct arrayHashMap {
+        pair *buckets[HASH_MAP_DEFAULT_SIZE];
+    };
+
+    typedef struct arrayHashMap arrayHashMap;
+
+    /* 哈希表初始化函数 */
+    arrayHashMap *newArrayHashMap() {
+        arrayHashMap *map = malloc(sizeof(arrayHashMap));
+        return map;
+    }
+
+    /* 添加操作 */
+    void put(arrayHashMap *d, const int key, const char *val) {
+        pair *pair = malloc(sizeof(pair));
+        pair->key = key;
+        pair->val = malloc(strlen(val) + 1);
+        strcpy(pair->val, val);
+
+        int index = hashFunc(key);
+        d->buckets[index] = pair;
+    }
+
+    /* 删除操作 */
+    void removeItem(arrayHashMap *d, const int key) {
+        int index = hashFunc(key);
+        free(d->buckets[index]->val);
+        free(d->buckets[index]);
+        d->buckets[index] = NULL;
+    }
+
+    /* 获取所有键值对 */
+    void pairSet(arrayHashMap *d, mapSet *set) {
+        pair *entries;
+        int i = 0, index = 0;
+        int total = 0;
+
+        /* 统计有效键值对数量 */
+        for (i = 0; i < HASH_MAP_DEFAULT_SIZE; i++) {
+            if (d->buckets[i] != NULL) {
+                total++;
+            }
+        }
+
+        entries = malloc(sizeof(pair) * total);
+        for (i = 0; i < HASH_MAP_DEFAULT_SIZE; i++) {
+            if (d->buckets[i] != NULL) {
+                entries[index].key = d->buckets[i]->key;
+                entries[index].val = malloc(strlen(d->buckets[i]->val + 1));
+                strcpy(entries[index].val, d->buckets[i]->val);
+                index++;
+            }
+        }
+
+        set->set = entries;
+        set->len = total;
+    }
+
+    /* 获取所有键 */
+    void keySet(arrayHashMap *d, mapSet *set) {
+        int *keys;
+        int i = 0, index = 0;
+        int total = 0;
+
+        /* 统计有效键值对数量 */
+        for (i = 0; i < HASH_MAP_DEFAULT_SIZE; i++) {
+            if (d->buckets[i] != NULL) {
+                total++;
+            }
+        }
+
+        keys = malloc(total * sizeof(int));
+        for (i = 0; i < HASH_MAP_DEFAULT_SIZE; i++) {
+            if (d->buckets[i] != NULL) {
+                keys[index] = d->buckets[i]->key;
+                index++;
+            }
+        }
+
+        set->set = keys;
+        set->len = total;
+    }
+
+    /* 获取所有值 */
+    void valueSet(arrayHashMap *d, mapSet *set) {
+        char **vals;
+        int i = 0, index = 0;
+        int total = 0;
+
+        /* 统计有效键值对数量 */
+        for (i = 0; i < HASH_MAP_DEFAULT_SIZE; i++) {
+            if (d->buckets[i] != NULL) {
+                total++;
+            }
+        }
+
+        vals = malloc(total * sizeof(char *));
+        for (i = 0; i < HASH_MAP_DEFAULT_SIZE; i++) {
+            if (d->buckets[i] != NULL) {
+                vals[index] = d->buckets[i]->val;
+                index++;
+            }
+        }
+
+        set->set = vals;
+        set->len = total;
+    }
+
+    /* 打印哈希表 */
+    void print(arrayHashMap *d) {
+        int i;
+        mapSet set;
+        pairSet(d, &set);
+        pair *entries = (pair *)set.set;
+        for (i = 0; i < set.len; i++) {
+            printf("%d -> %s\n", entries[i].key, entries[i].val);
+        }
+        free(set.set);
+    }
     ```
 
 === "Zig"