trie_using_hashmap.cpp File Reference

Implementation of Trie data structure using HashMap for different characters and method for predicting words based on prefix. More...

#include <cassert>
#include <iostream>
#include <memory>
#include <stack>
#include <unordered_map>
#include <vector>

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Classes
class	data_structures::trie_using_hashmap::Trie
	Trie class, implementation of trie using hashmap in each trie node for all the characters of char16_t(UTF-16)type with methods to insert, delete, search, start with and to recommend words based on a given prefix. More...
struct	data_structures::trie_using_hashmap::Trie::Node
	struct representing a trie node. More...

Namespaces
namespace	data_structures
	for IO operations
namespace	trie_using_hashmap
	Functions for Trie data structure using hashmap implementation.

Functions
static void	test ()
	Self-test implementations.
int	main ()
	Main function.

Detailed Description

Implementation of Trie data structure using HashMap for different characters and method for predicting words based on prefix.

Author

Venkata Bharath

The Trie data structure is implemented using unordered map to use memory optimally, predict_words method is developed to recommend words based on a given prefix along with other methods insert, delete, search, startwith in trie.

See also

trie_modern.cpp for difference

Function Documentation

main()

int main

(

void

)

Main function.

Returns

0 on exit

           {
    test();  // run self-test implementaions
    return 0;
}

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test()

static void test ( )

static

Self-test implementations.

Returns

void

                   {
    data_structures::trie_using_hashmap::Trie obj;
    // Inserting data into trie using the insert
    // method and testing it with search method
    obj.insert("app");
    obj.insert("abscond");
    obj.insert("about");
    obj.insert("apps");
    obj.insert("apen");
    obj.insert("apples");
    obj.insert("apple");
    obj.insert("approach");
    obj.insert("bus");
    obj.insert("buses");
    obj.insert("Apple");
    obj.insert("Bounce");
 
    assert(!obj.search("appy"));
    std::cout << "appy is not a word in trie" << std::endl;
 
    assert(!obj.search("car"));
    std::cout << "car is not a word in trie" << std::endl;
    assert(obj.search("app"));
    assert(obj.search("apple"));
    assert(obj.search("apples"));
    assert(obj.search("apps"));
    assert(obj.search("apen"));
    assert(obj.search("approach"));
    assert(obj.search("about"));
    assert(obj.search("abscond"));
    assert(obj.search("bus"));
    assert(obj.search("buses"));
    assert(obj.search("Bounce"));
    assert(obj.search("Apple"));
 
    std::cout << "All the Inserted words are present in the trie" << std::endl;
 
    // test for startwith prefix method
    assert(!obj.startwith("approachs"));
    assert(obj.startwith("approach"));
    assert(obj.startwith("about"));
    assert(!obj.startwith("appy"));
    assert(obj.startwith("abscond"));
    assert(obj.startwith("bus"));
    assert(obj.startwith("buses"));
    assert(obj.startwith("Bounce"));
    assert(obj.startwith("Apple"));
    assert(obj.startwith("abs"));
    assert(obj.startwith("b"));
    assert(obj.startwith("bus"));
    assert(obj.startwith("Bo"));
    assert(obj.startwith("A"));
    assert(!obj.startwith("Ca"));
 
    assert(!obj.startwith("C"));
 
    std::cout << "All the tests passed for startwith method" << std::endl;
 
    // test for predict_words/recommendation of words based on a given prefix
 
    std::vector<std::string> pred_words = obj.predict_words("a");
 
    for (const std::string& str : obj.predict_words("a")) {
        std::cout << str << std::endl;
    }
    assert(pred_words.size() == 8);
    std::cout << "Returned all words that start with prefix a " << std::endl;
    pred_words = obj.predict_words("app");
 
    for (const std::string& str : pred_words) {
        std::cout << str << std::endl;
    }
 
    assert(pred_words.size() == 5);
    std::cout << "Returned all words that start with prefix app " << std::endl;
    pred_words = obj.predict_words("A");
 
    for (const std::string& str : pred_words) {
        std::cout << str << std::endl;
    }
 
    assert(pred_words.size() == 1);
    std::cout << "Returned all words that start with prefix A " << std::endl;
    pred_words = obj.predict_words("bu");
 
    for (const std::string& str : pred_words) {
        std::cout << str << std::endl;
    }
 
    assert(pred_words.size() == 2);
    std::cout << "Returned all words that start with prefix bu " << std::endl;
 
    // tests for delete method
 
    obj.delete_word("app");
    assert(!obj.search("app"));
    std::cout << "word app is deleted sucessful" << std::endl;
 
    pred_words = obj.predict_words("app");
    for (const std::string& str : pred_words) {
        std::cout << str << std::endl;
    }
    assert(pred_words.size() == 4);
    std::cout << "app is deleted sucessful" << std::endl;
 
    // test case for Chinese language
 
    obj.insert("苹果");
    assert(obj.startwith("苹"));
    pred_words = obj.predict_words("h");
 
    assert(pred_words.size() == 0);
    std::cout << "No word starts with prefix h in trie" << std::endl;
 
    std::cout << "All tests passed" << std::endl;
}

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