Develop An Algorithm To Search And Remove Data From
Develop An Algorithm To Search And Remove Data Fro
Develop an algorithm to search and remove data from a hash table using the open addressing technique. The goal is to implement a hash table with open addressing and linear probing. The implementation requires defining specific methods within the OpenAddrHashTable class, including put, searchPosition, remove, and get. Additionally, a container class named OpenAddrPair will hold key-value pairs and include a flag to indicate deletion status. This flag facilitates overwriting deleted entries during insertions, optimizing search and remove operations. The pseudocode provided demonstrates the insertion and search strategies via linear probing, emphasizing collision resolution by sequentially probing subsequent slots until an empty or matching slot is found. Proper handling of deleted flags and careful probing are crucial to efficiently manage the hash table. Your task involves coding these methods to conform with the provided pseudocode, ensuring correct behavior when adding, searching, and removing data from the hash table.
Paper For Above instruction
The task of implementing a hash table utilizing open addressing with linear probing is a fundamental concept in data structures, designed to ensure efficient data storage and retrieval. This paper discusses the development of such a system by elaborating on the algorithmic strategies, class design, and implementation specifics aligned with the provided pseudocode instructions.
Introduction
Hash tables are a cornerstone of efficient data management, enabling rapid access to stored data through keys. Open addressing with linear probing resolves collisions by probing subsequent slots for available space, thereby maintaining compact storage without needing separate chaining. Implementing this method requires careful handling of probing sequences, deletion markers, and overwriting strategies to prevent search failures and maintain performance. The current project centers on creating a Java-based class OpenAddrHashTable that manages key-value pairs using an array-backed structure supported by open addressing techniques.
Design and Implementation of the Hash Table
The core components entail the put, searchPosition, remove, and get methods, along with an auxiliary class OpenAddrPair to encapsulate key-value pairs. The hash function's role is to convert keys into array indices, while linear probing searches for an empty slot or the target key in case of collisions. The approach adheres to the provided pseudocode snippets, ensuring consistency and correctness.
1. Insertion: `put` Method
The put method computes the initial hash index for the key and probes linearly:
```java
public void put(K key, V value) {
int s = array.length;
int hashValue = hashProvider.hash(key) % s;
int i = 0;
while (i
if (array[(hashValue + i) % s].getKey().equals(key)) {
// Overwrite existing key
array[(hashValue + i) % s] = new OpenAddrPair(key, value, false);
return;
}
i++;
}
if (i
array[(hashValue + i) % s] = new OpenAddrPair(key, value, false);
}
}
```
This process ensures that new key-value pairs are inserted in the first available slot, replacing an item if it was previously deleted.
2. Search: `searchPosition` Method
The searchPosition method locates the index of a key, returning -1 if absent:
```java
private int searchPosition(K key) {
int s = array.length;
int hashValue = hashProvider.hash(key) % s;
int i = 0;
while (i
int index = (hashValue + i) % s;
OpenAddrPair
if (current == null) {
// Empty slot indicates key not present
return -1;
} else if (!current.isDeleted() && current.getKey().equals(key)) {
return index;
}
i++;
}
return -1;
}
```
This linear probing approach ensures all possible locations are checked before concluding absence.
3. Removal: `remove` Method
Removing an element involves marking the slot as deleted rather than nullifying it, preserving probing chains:
```java
public void remove(K key) {
int pos = searchPosition(key);
if (pos >= 0) {
array[pos].setDeleted(true);
}
}
```
Utilizing a deletion flag avoids breaking the probing sequence and maintains search integrity.
4. Retrieval: `get` Method
The get method retrieves the value associated with a key:
```java
public Optional
int s = array.length;
int hashValue = hashProvider.hash(key) % s;
int i = 0;
while (i
int index = (hashValue + i) % s;
OpenAddrPair
if (current == null) {
return Optional.empty();
} else if (!current.isDeleted() && current.getKey().equals(key)) {
return Optional.ofNullable(current.getValue());
}
i++;
}
return Optional.empty();
}
```
This method probes to find the matching key, skipping deleted positions.
Conclusion
Implementing an open addressing hash table with linear probing requires meticulous attention to probing strategies, deletion handling, and careful array management. Utilizing a deletion flag within each slot preserves the integrity of search sequences, facilitating efficient insertions and removals. The provided pseudocode and class structure serve as a blueprint for creating robust hash table implementations in Java, vital for supporting high-performance data storage solutions in various applications.
References
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