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
2026-06-29 00:54:26 +00:00 · 2024-05-06 05:21:51 +08:00
parent b5e198db7d
commit 1c0f350ad6
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+/**
+ * File: hash_map_open_addressing.java
+ * Created Time: 2023-06-13
+ * Author: krahets (krahets@163.com)
+ */
+
+package chapter_hashing;
+
+/* Open addressing hash table */
+class HashMapOpenAddressing {
+    private int size; // Number of key-value pairs
+    private int capacity = 4; // Hash table capacity
+    private final double loadThres = 2.0 / 3.0; // Load factor threshold for triggering expansion
+    private final int extendRatio = 2; // Expansion multiplier
+    private Pair[] buckets; // Bucket array
+    private final Pair TOMBSTONE = new Pair(-1, "-1"); // Removal mark
+
+    /* Constructor */
+    public HashMapOpenAddressing() {
+        size = 0;
+        buckets = new Pair[capacity];
+    }
+
+    /* Hash function */
+    private int hashFunc(int key) {
+        return key % capacity;
+    }
+
+    /* Load factor */
+    private double loadFactor() {
+        return (double) size / capacity;
+    }
+
+    /* Search for the bucket index corresponding to key */
+    private int findBucket(int key) {
+        int index = hashFunc(key);
+        int firstTombstone = -1;
+        // Linear probing, break when encountering an empty bucket
+        while (buckets[index] != null) {
+            // 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 */
+    public 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] != null && buckets[index] != TOMBSTONE) {
+            return buckets[index].val;
+        }
+        // If the key-value pair does not exist, return null
+        return null;
+    }
+
+    /* Add operation */
+    public 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] != null && 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 */
+    public 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] != null && buckets[index] != TOMBSTONE) {
+            buckets[index] = TOMBSTONE;
+            size--;
+        }
+    }
+
+    /* Extend hash table */
+    private void extend() {
+        // Temporarily store the original hash table
+        Pair[] bucketsTmp = buckets;
+        // Initialize the extended new hash table
+        capacity *= extendRatio;
+        buckets = new Pair[capacity];
+        size = 0;
+        // Move key-value pairs from the original hash table to the new hash table
+        for (Pair pair : bucketsTmp) {
+            if (pair != null && pair != TOMBSTONE) {
+                put(pair.key, pair.val);
+            }
+        }
+    }
+
+    /* Print hash table */
+    public void print() {
+        for (Pair pair : buckets) {
+            if (pair == null) {
+                System.out.println("null");
+            } else if (pair == TOMBSTONE) {
+                System.out.println("TOMBSTONE");
+            } else {
+                System.out.println(pair.key + " -> " + pair.val);
+            }
+        }
+    }
+}
+
+public class hash_map_open_addressing {
+    public static void main(String[] args) {
+        // Initialize hash table
+        HashMapOpenAddressing hashmap = new HashMapOpenAddressing();
+
+        // 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");
+        System.out.println("\nAfter adding, the hash table is\nKey -> Value");
+        hashmap.print();
+
+        // Query operation
+        // Enter key to the hash table, get value val
+        String name = hashmap.get(13276);
+        System.out.println("\nEnter student ID 13276, found name " + name);
+
+        // Remove operation
+        // Remove key-value pair (key, val) from the hash table
+        hashmap.remove(16750);
+        System.out.println("\nAfter removing 16750, the hash table is\nKey -> Value");
+        hashmap.print();
+    }
+}