Add the initial EN translation for C++ code (#1346)

en/codes/cpp/chapter_hashing/CMakeLists.txt

@@ -0,0 +1,6 @@
+add_executable(hash_map hash_map.cpp)
+add_executable(array_hash_map_test array_hash_map_test.cpp)
+add_executable(hash_map_chaining hash_map_chaining.cpp)
+add_executable(hash_map_open_addressing hash_map_open_addressing.cpp)
+add_executable(simple_hash simple_hash.cpp)
+add_executable(built_in_hash built_in_hash.cpp)

en/codes/cpp/chapter_hashing/array_hash_map.cpp

@@ -0,0 +1,110 @@
+/**
+ * File: array_hash_map.cpp
+ * Created Time: 2022-12-14
+ * Author: msk397 (machangxinq@gmail.com)
+ */
+
+#include "../utils/common.hpp"
+
+/* Key-value pair */
+struct Pair {
+  public:
+    int key;
+    string val;
+    Pair(int key, string val) {
+        this->key = key;
+        this->val = val;
+    }
+};
+
+/* Hash table based on array implementation */
+class ArrayHashMap {
+  private:
+    vector<Pair *> buckets;
+
+  public:
+    ArrayHashMap() {
+        // Initialize an array, containing 100 buckets
+        buckets = vector<Pair *>(100);
+    }
+
+    ~ArrayHashMap() {
+        // Free memory
+        for (const auto &bucket : buckets) {
+            delete bucket;
+        }
+        buckets.clear();
+    }
+
+    /* Hash function */
+    int hashFunc(int key) {
+        int index = key % 100;
+        return index;
+    }
+
+    /* Query operation */
+    string get(int key) {
+        int index = hashFunc(key);
+        Pair *pair = buckets[index];
+        if (pair == nullptr)
+            return "";
+        return pair->val;
+    }
+
+    /* Add operation */
+    void put(int key, string val) {
+        Pair *pair = new Pair(key, val);
+        int index = hashFunc(key);
+        buckets[index] = pair;
+    }
+
+    /* Remove operation */
+    void remove(int key) {
+        int index = hashFunc(key);
+        // Free memory and set to nullptr
+        delete buckets[index];
+        buckets[index] = nullptr;
+    }
+
+    /* Get all key-value pairs */
+    vector<Pair *> pairSet() {
+        vector<Pair *> pairSet;
+        for (Pair *pair : buckets) {
+            if (pair != nullptr) {
+                pairSet.push_back(pair);
+            }
+        }
+        return pairSet;
+    }
+
+    /* Get all keys */
+    vector<int> keySet() {
+        vector<int> keySet;
+        for (Pair *pair : buckets) {
+            if (pair != nullptr) {
+                keySet.push_back(pair->key);
+            }
+        }
+        return keySet;
+    }
+
+    /* Get all values */
+    vector<string> valueSet() {
+        vector<string> valueSet;
+        for (Pair *pair : buckets) {
+            if (pair != nullptr) {
+                valueSet.push_back(pair->val);
+            }
+        }
+        return valueSet;
+    }
+
+    /* Print hash table */
+    void print() {
+        for (Pair *kv : pairSet()) {
+            cout << kv->key << " -> " << kv->val << endl;
+        }
+    }
+};
+
+// See test case in array_hash_map_test.cpp

en/codes/cpp/chapter_hashing/array_hash_map_test.cpp

@@ -0,0 +1,52 @@
+/**
+ * File: array_hash_map_test.cpp
+ * Created Time: 2022-12-14
+ * Author: msk397 (machangxinq@gmail.com)
+ */
+
+#include "./array_hash_map.cpp"
+
+/* Driver Code */
+int main() {
+    /* Initialize hash table */
+    ArrayHashMap map = ArrayHashMap();
+
+    /* Add operation */
+    // Add key-value pair (key, value) to the hash table
+    map.put(12836, "Ha");
+    map.put(15937, "Luo");
+    map.put(16750, "Suan");
+    map.put(13276, "Fa");
+    map.put(10583, "Ya");
+    cout << "\nAfter adding, the hash table is\nKey -> Value" << endl;
+    map.print();
+
+    /* Query operation */
+    // Enter key to the hash table, get value
+    string name = map.get(15937);
+    cout << "\nEnter student ID 15937, found name " << name << endl;
+
+    /* Remove operation */
+    // Remove key-value pair (key, value) from the hash table
+    map.remove(10583);
+    cout << "\nAfter removing 10583, the hash table is\nKey -> Value" << endl;
+    map.print();
+
+    /* Traverse hash table */
+    cout << "\nTraverse key-value pairs Key->Value" << endl;
+    for (auto kv : map.pairSet()) {
+        cout << kv->key << " -> " << kv->val << endl;
+    }
+
+    cout << "\nIndividually traverse keys Key" << endl;
+    for (auto key : map.keySet()) {
+        cout << key << endl;
+    }
+
+    cout << "\nIndividually traverse values Value" << endl;
+    for (auto val : map.valueSet()) {
+        cout << val << endl;
+    }
+
+    return 0;
+}

en/codes/cpp/chapter_hashing/built_in_hash.cpp

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+/**
+ * File: built_in_hash.cpp
+ * Created Time: 2023-06-21
+ * Author: krahets (krahets@163.com)
+ */
+
+#include "../utils/common.hpp"
+
+/* Driver Code */
+int main() {
+    int num = 3;
+    size_t hashNum = hash<int>()(num);
+    cout << "The hash value of integer " << num << " is " << hashNum << "\n";
+
+    bool bol = true;
+    size_t hashBol = hash<bool>()(bol);
+    cout << "The hash value of boolean " << bol << " is " << hashBol << "\n";
+
+    double dec = 3.14159;
+    size_t hashDec = hash<double>()(dec);
+    cout << "The hash value of decimal " << dec << " is " << hashDec << "\n";
+
+    string str = "Hello algorithm";
+    size_t hashStr = hash<string>()(str);
+    cout << "The hash value of string " << str << " is " << hashStr << "\n";
+
+    // In C++, the built-in std:hash() only provides hash values for basic data types
+    // Hash value calculation for arrays and objects must be implemented manually
+}

en/codes/cpp/chapter_hashing/hash_map.cpp

@@ -0,0 +1,46 @@
+/**
+ * File: hash_map.cpp
+ * Created Time: 2022-12-14
+ * Author: msk397 (machangxinq@gmail.com)
+ */
+
+#include "../utils/common.hpp"
+
+/* Driver Code */
+int main() {
+    /* Initialize hash table */
+    unordered_map<int, string> map;
+
+    /* Add operation */
+    // Add key-value pair (key, value) to the hash table
+    map[12836] = "Ha";
+    map[15937] = "Luo";
+    map[16750] = "Suan";
+    map[13276] = "Fa";
+    map[10583] = "Ya";
+    cout << "\nAfter adding, the hash table is\nKey -> Value" << endl;
+    printHashMap(map);
+
+    /* Query operation */
+    // Enter key to the hash table, get value
+    string name = map[15937];
+    cout << "\nEnter student ID 15937, found name " << name << endl;
+
+    /* Remove operation */
+    // Remove key-value pair (key, value) from the hash table
+    map.erase(10583);
+    cout << "\nAfter removing 10583, the hash table is\nKey -> Value" << endl;
+    printHashMap(map);
+
+    /* Traverse hash table */
+    cout << "\nTraverse key-value pairs Key->Value" << endl;
+    for (auto kv : map) {
+        cout << kv.first << " -> " << kv.second << endl;
+    }
+    cout << "\nIterate through Key->Value using an iterator" << endl;
+    for (auto iter = map.begin(); iter != map.end(); iter++) {
+        cout << iter->first << "->" << iter->second << endl;
+    }
+
+    return 0;
+}

en/codes/cpp/chapter_hashing/hash_map_chaining.cpp

@@ -0,0 +1,150 @@
+/**
+ * File: hash_map_chaining.cpp
+ * Created Time: 2023-06-13
+ * Author: krahets (krahets@163.com)
+ */
+
+#include "./array_hash_map.cpp"
+
+/* Chained address hash table */
+class HashMapChaining {
+  private:
+    int size;                       // Number of key-value pairs
+    int capacity;                   // Hash table capacity
+    double loadThres;               // Load factor threshold for triggering expansion
+    int extendRatio;                // Expansion multiplier
+    vector<vector<Pair *>> buckets; // Bucket array
+
+  public:
+    /* Constructor */
+    HashMapChaining() : size(0), capacity(4), loadThres(2.0 / 3.0), extendRatio(2) {
+        buckets.resize(capacity);
+    }
+
+    /* Destructor */
+    ~HashMapChaining() {
+        for (auto &bucket : buckets) {
+            for (Pair *pair : bucket) {
+                // Free memory
+                delete pair;
+            }
+        }
+    }
+
+    /* Hash function */
+    int hashFunc(int key) {
+        return key % capacity;
+    }
+
+    /* Load factor */
+    double loadFactor() {
+        return (double)size / (double)capacity;
+    }
+
+    /* Query operation */
+    string get(int key) {
+        int index = hashFunc(key);
+        // Traverse the bucket, if the key is found, return the corresponding val
+        for (Pair *pair : buckets[index]) {
+            if (pair->key == key) {
+                return pair->val;
+            }
+        }
+        // If key not found, return an empty string
+        return "";
+    }
+
+    /* Add operation */
+    void put(int key, string val) {
+        // When the load factor exceeds the threshold, perform expansion
+        if (loadFactor() > loadThres) {
+            extend();
+        }
+        int index = hashFunc(key);
+        // Traverse the bucket, if the specified key is encountered, update the corresponding val and return
+        for (Pair *pair : buckets[index]) {
+            if (pair->key == key) {
+                pair->val = val;
+                return;
+            }
+        }
+        // If the key is not found, add the key-value pair to the end
+        buckets[index].push_back(new Pair(key, val));
+        size++;
+    }
+
+    /* Remove operation */
+    void remove(int key) {
+        int index = hashFunc(key);
+        auto &bucket = buckets[index];
+        // Traverse the bucket, remove the key-value pair from it
+        for (int i = 0; i < bucket.size(); i++) {
+            if (bucket[i]->key == key) {
+                Pair *tmp = bucket[i];
+                bucket.erase(bucket.begin() + i); // Remove key-value pair
+                delete tmp;                       // Free memory
+                size--;
+                return;
+            }
+        }
+    }
+
+    /* Extend hash table */
+    void extend() {
+        // Temporarily store the original hash table
+        vector<vector<Pair *>> bucketsTmp = buckets;
+        // Initialize the extended new hash table
+        capacity *= extendRatio;
+        buckets.clear();
+        buckets.resize(capacity);
+        size = 0;
+        // Move key-value pairs from the original hash table to the new hash table
+        for (auto &bucket : bucketsTmp) {
+            for (Pair *pair : bucket) {
+                put(pair->key, pair->val);
+                // Free memory
+                delete pair;
+            }
+        }
+    }
+
+    /* Print hash table */
+    void print() {
+        for (auto &bucket : buckets) {
+            cout << "[";
+            for (Pair *pair : bucket) {
+                cout << pair->key << " -> " << pair->val << ", ";
+            }
+            cout << "]\n";
+        }
+    }
+};
+
+/* Driver Code */
+int main() {
+    /* Initialize hash table */
+    HashMapChaining map = HashMapChaining();
+
+    /* Add operation */
+    // Add key-value pair (key, value) to the hash table
+    map.put(12836, "Ha");
+    map.put(15937, "Luo");
+    map.put(16750, "Suan");
+    map.put(13276, "Fa");
+    map.put(10583, "Ya");
+    cout << "\nAfter adding, the hash table is\nKey -> Value" << endl;
+    map.print();
+
+    /* Query operation */
+    // Enter key to the hash table, get value
+    string name = map.get(13276);
+    cout << "\nEnter student ID 13276, found name " << name << endl;
+
+    /* Remove operation */
+    // Remove key-value pair (key, value) from the hash table
+    map.remove(12836);
+    cout << "\nAfter removing 12836, the hash table is\nKey -> Value" << endl;
+    map.print();
+
+    return 0;
+}

en/codes/cpp/chapter_hashing/hash_map_open_addressing.cpp

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+/**
+ * File: hash_map_open_addressing.cpp
+ * Created Time: 2023-06-13
+ * Author: krahets (krahets@163.com)
+ */
+
+#include "./array_hash_map.cpp"
+
+/* Open addressing hash table */
+class HashMapOpenAddressing {
+  private:
+    int size;                             // Number of key-value pairs
+    int capacity = 4;                     // Hash table capacity
+    const double loadThres = 2.0 / 3.0;     // Load factor threshold for triggering expansion
+    const int extendRatio = 2;            // Expansion multiplier
+    vector<Pair *> buckets;               // Bucket array
+    Pair *TOMBSTONE = new Pair(-1, "-1"); // Removal mark
+
+  public:
+    /* Constructor */
+    HashMapOpenAddressing() : size(0), buckets(capacity, nullptr) {
+    }
+
+    /* Destructor */
+    ~HashMapOpenAddressing() {
+        for (Pair *pair : buckets) {
+            if (pair != nullptr && pair != TOMBSTONE) {
+                delete pair;
+            }
+        }
+        delete TOMBSTONE;
+    }
+
+    /* Hash function */
+    int hashFunc(int key) {
+        return key % capacity;
+    }
+
+    /* Load factor */
+    double loadFactor() {
+        return (double)size / capacity;
+    }
+
+    /* Search for the bucket index corresponding to key */
+    int findBucket(int key) {
+        int index = hashFunc(key);
+        int firstTombstone = -1;
+        // Linear probing, break when encountering an empty bucket
+        while (buckets[index] != nullptr) {
+            // If the key is encountered, return the corresponding bucket index
+            if (buckets[index]->key == key) {
+                // If a removal mark was encountered earlier, move the key-value pair to that index
+                if (firstTombstone != -1) {
+                    buckets[firstTombstone] = buckets[index];
+                    buckets[index] = TOMBSTONE;
+                    return firstTombstone; // Return the moved bucket index
+                }
+                return index; // Return bucket index
+            }
+            // Record the first encountered removal mark
+            if (firstTombstone == -1 && buckets[index] == TOMBSTONE) {
+                firstTombstone = index;
+            }
+            // Calculate the bucket index, return to the head if exceeding the tail
+            index = (index + 1) % capacity;
+        }
+        // If the key does not exist, return the index of the insertion point
+        return firstTombstone == -1 ? index : firstTombstone;
+    }
+
+    /* Query operation */
+    string get(int key) {
+        // Search for the bucket index corresponding to key
+        int index = findBucket(key);
+        // If the key-value pair is found, return the corresponding val
+        if (buckets[index] != nullptr && buckets[index] != TOMBSTONE) {
+            return buckets[index]->val;
+        }
+        // If key-value pair does not exist, return an empty string
+        return "";
+    }
+
+    /* Add operation */
+    void put(int key, string val) {
+        // When the load factor exceeds the threshold, perform expansion
+        if (loadFactor() > loadThres) {
+            extend();
+        }
+        // Search for the bucket index corresponding to key
+        int index = findBucket(key);
+        // If the key-value pair is found, overwrite val and return
+        if (buckets[index] != nullptr && buckets[index] != TOMBSTONE) {
+            buckets[index]->val = val;
+            return;
+        }
+        // If the key-value pair does not exist, add the key-value pair
+        buckets[index] = new Pair(key, val);
+        size++;
+    }
+
+    /* Remove operation */
+    void remove(int key) {
+        // Search for the bucket index corresponding to key
+        int index = findBucket(key);
+        // If the key-value pair is found, cover it with a removal mark
+        if (buckets[index] != nullptr && buckets[index] != TOMBSTONE) {
+            delete buckets[index];
+            buckets[index] = TOMBSTONE;
+            size--;
+        }
+    }
+
+    /* Extend hash table */
+    void extend() {
+        // Temporarily store the original hash table
+        vector<Pair *> bucketsTmp = buckets;
+        // Initialize the extended new hash table
+        capacity *= extendRatio;
+        buckets = vector<Pair *>(capacity, nullptr);
+        size = 0;
+        // Move key-value pairs from the original hash table to the new hash table
+        for (Pair *pair : bucketsTmp) {
+            if (pair != nullptr && pair != TOMBSTONE) {
+                put(pair->key, pair->val);
+                delete pair;
+            }
+        }
+    }
+
+    /* Print hash table */
+    void print() {
+        for (Pair *pair : buckets) {
+            if (pair == nullptr) {
+                cout << "nullptr" << endl;
+            } else if (pair == TOMBSTONE) {
+                cout << "TOMBSTONE" << endl;
+            } else {
+                cout << pair->key << " -> " << pair->val << endl;
+            }
+        }
+    }
+};
+
+/* Driver Code */
+int main() {
+    // Initialize hash table
+    HashMapOpenAddressing hashmap;
+
+    // Add operation
+    // Add key-value pair (key, val) to the hash table
+    hashmap.put(12836, "Ha");
+    hashmap.put(15937, "Luo");
+    hashmap.put(16750, "Suan");
+    hashmap.put(13276, "Fa");
+    hashmap.put(10583, "Ya");
+    cout << "\nAfter adding, the hash table is\nKey -> Value" << endl;
+    hashmap.print();
+
+    // Query operation
+    // Enter key to the hash table, get value val
+    string name = hashmap.get(13276);
+    cout << "\nEnter student ID 13276, found name " << name << endl;
+
+    // Remove operation
+    // Remove key-value pair (key, val) from the hash table
+    hashmap.remove(16750);
+    cout << "\nAfter removing 16750, the hash table is\nKey -> Value" << endl;
+    hashmap.print();
+
+    return 0;
+}

en/codes/cpp/chapter_hashing/simple_hash.cpp

@@ -0,0 +1,66 @@
+/**
+ * File: simple_hash.cpp
+ * Created Time: 2023-06-21
+ * Author: krahets (krahets@163.com)
+ */
+
+#include "../utils/common.hpp"
+
+/* Additive hash */
+int addHash(string key) {
+    long long hash = 0;
+    const int MODULUS = 1000000007;
+    for (unsigned char c : key) {
+        hash = (hash + (int)c) % MODULUS;
+    }
+    return (int)hash;
+}
+
+/* Multiplicative hash */
+int mulHash(string key) {
+    long long hash = 0;
+    const int MODULUS = 1000000007;
+    for (unsigned char c : key) {
+        hash = (31 * hash + (int)c) % MODULUS;
+    }
+    return (int)hash;
+}
+
+/* XOR hash */
+int xorHash(string key) {
+    int hash = 0;
+    const int MODULUS = 1000000007;
+    for (unsigned char c : key) {
+        hash ^= (int)c;
+    }
+    return hash & MODULUS;
+}
+
+/* Rotational hash */
+int rotHash(string key) {
+    long long hash = 0;
+    const int MODULUS = 1000000007;
+    for (unsigned char c : key) {
+        hash = ((hash << 4) ^ (hash >> 28) ^ (int)c) % MODULUS;
+    }
+    return (int)hash;
+}
+
+/* Driver Code */
+int main() {
+    string key = "Hello algorithm";
+
+    int hash = addHash(key);
+    cout << "Additive hash value is " << hash << endl;
+
+    hash = mulHash(key);
+    cout << "Multiplicative hash value is " << hash << endl;
+
+    hash = xorHash(key);
+    cout << "XOR hash value is " << hash << endl;
+
+    hash = rotHash(key);
+    cout << "Rotational hash value is " << hash << endl;
+
+    return 0;
+}