translation: Add Python and Java code for EN version (#1345)

* Add the intial translation of code of all the languages * test * revert * Remove * Add Python and Java code for EN version
2026-04-03 10:40:15 +08:00 · 2024-05-06 05:21:51 +08:00
parent b5e198db7d
commit 1c0f350ad6
174 changed files with 12349 additions and 0 deletions
--- a/en/codes/java/chapter_hashing/hash_map_chaining.java
+++ b/en/codes/java/chapter_hashing/hash_map_chaining.java
@@ -0,0 +1,148 @@
+/**
+ * File: hash_map_chaining.java
+ * Created Time: 2023-06-13
+ * Author: krahets (krahets@163.com)
+ */
+
+package chapter_hashing;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/* Chained address hash table */
+class HashMapChaining {
+    int size; // Number of key-value pairs
+    int capacity; // Hash table capacity
+    double loadThres; // Load factor threshold for triggering expansion
+    int extendRatio; // Expansion multiplier
+    List<List<Pair>> buckets; // Bucket array
+
+    /* Constructor */
+    public HashMapChaining() {
+        size = 0;
+        capacity = 4;
+        loadThres = 2.0 / 3.0;
+        extendRatio = 2;
+        buckets = new ArrayList<>(capacity);
+        for (int i = 0; i < capacity; i++) {
+            buckets.add(new ArrayList<>());
+        }
+    }
+
+    /* Hash function */
+    int hashFunc(int key) {
+        return key % capacity;
+    }
+
+    /* Load factor */
+    double loadFactor() {
+        return (double) size / capacity;
+    }
+
+    /* Query operation */
+    String get(int key) {
+        int index = hashFunc(key);
+        List<Pair> bucket = buckets.get(index);
+        // Traverse the bucket, if the key is found, return the corresponding val
+        for (Pair pair : bucket) {
+            if (pair.key == key) {
+                return pair.val;
+            }
+        }
+        // If key is not found, return null
+        return null;
+    }
+
+    /* 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);
+        List<Pair> bucket = buckets.get(index);
+        // Traverse the bucket, if the specified key is encountered, update the corresponding val and return
+        for (Pair pair : bucket) {
+            if (pair.key == key) {
+                pair.val = val;
+                return;
+            }
+        }
+        // If the key is not found, add the key-value pair to the end
+        Pair pair = new Pair(key, val);
+        bucket.add(pair);
+        size++;
+    }
+
+    /* Remove operation */
+    void remove(int key) {
+        int index = hashFunc(key);
+        List<Pair> bucket = buckets.get(index);
+        // Traverse the bucket, remove the key-value pair from it
+        for (Pair pair : bucket) {
+            if (pair.key == key) {
+                bucket.remove(pair);
+                size--;
+                break;
+            }
+        }
+    }
+
+    /* Extend hash table */
+    void extend() {
+        // Temporarily store the original hash table
+        List<List<Pair>> bucketsTmp = buckets;
+        // Initialize the extended new hash table
+        capacity *= extendRatio;
+        buckets = new ArrayList<>(capacity);
+        for (int i = 0; i < capacity; i++) {
+            buckets.add(new ArrayList<>());
+        }
+        size = 0;
+        // Move key-value pairs from the original hash table to the new hash table
+        for (List<Pair> bucket : bucketsTmp) {
+            for (Pair pair : bucket) {
+                put(pair.key, pair.val);
+            }
+        }
+    }
+
+    /* Print hash table */
+    void print() {
+        for (List<Pair> bucket : buckets) {
+            List<String> res = new ArrayList<>();
+            for (Pair pair : bucket) {
+                res.add(pair.key + " -> " + pair.val);
+            }
+            System.out.println(res);
+        }
+    }
+}
+
+public class hash_map_chaining {
+    public static void main(String[] args) {
+        /* Initialize hash table */
+        HashMapChaining map = new 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");
+        System.out.println("\nAfter adding, the hash table is\nKey -> Value");
+        map.print();
+
+        /* Query operation */
+        // Enter key to the hash table, get value
+        String name = map.get(13276);
+        System.out.println("\nEnter student ID 13276, found name " + name);
+
+        /* Remove operation */
+        // Remove key-value pair (key, value) from the hash table
+        map.remove(12836);
+        System.out.println("\nAfter removing 12836, the hash table is\nKey -> Value");
+        map.print();
+    }
+}