Merge pull request #1689 from Abhinavcode13/patch-44

Create Bloomfilter.cpp

Author: akgmage

Hash Table/Bloomfilter.cpp

@@ -0,0 +1,66 @@
+#include <iostream>
+#include <vector>
+#include <bitset>
+#include <functional>
+
+class BloomFilter {
+private:
+    int size;                    // Size of the Bloom Filter bitset
+    std::vector<std::function<size_t(const std::string&)>> hash_functions;
+    std::bitset<1000000> bitset; // Bitset to represent the Bloom Filter
+
+public:
+    // Constructor to initialize the Bloom Filter with a given size and hash functions
+    BloomFilter(int size, std::vector<std::function<size_t(const std::string&)>> hash_functions)
+        : size(size), hash_functions(hash_functions) {}
+
+    // Function to add an element to the Bloom Filter
+    void add(const std::string& element) {
+        for (const auto& hash_function : hash_functions) {
+            size_t index = hash_function(element) % size;
+            bitset.set(index);
+        }
+    }
+
+    // Function to check if an element may exist in the Bloom Filter
+    bool contains(const std::string& element) {
+        for (const auto& hash_function : hash_functions) {
+            size_t index = hash_function(element) % size;
+            if (!bitset.test(index)) {
+                return false;  // If any bit is not set, the element is definitely not in the filter
+            }
+        }
+        return true; // If all bits are set, the element may exist in the filter (false positives are possible)
+    }
+};
+
+// Example hash function using std::hash
+size_t hash1(const std::string& str) {
+    return std::hash<std::string>{}(str);
+}
+
+// Example hash function using a custom hash function
+size_t hash2(const std::string& str) {
+    size_t hash = 0;
+    for (char c : str) {
+        hash = (hash * 31) + c;
+    }
+    return hash;
+}
+
+int main() {
+    // Create a Bloom Filter with a size of 1000000 and two hash functions
+    BloomFilter bloomFilter(1000000, {hash1, hash2});
+
+    // Add elements to the Bloom Filter
+    bloomFilter.add("apple");
+    bloomFilter.add("banana");
+    bloomFilter.add("cherry");
+
+    // Check if elements may exist in the Bloom Filter
+    std::cout << "Contains 'apple': " << bloomFilter.contains("apple") << std::endl;     // Should return 1 (true)
+    std::cout << "Contains 'grape': " << bloomFilter.contains("grape") << std::endl;     // Should return 0 (false)
+    std::cout << "Contains 'cherry': " << bloomFilter.contains("cherry") << std::endl;   // Should return 1 (true)
+    
+    return 0;
+}