Merge branch 'master' into master

Author: realstealthninja

DIRECTORY.md

@@ -302,6 +302,7 @@
   * [Kadanes3](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/others/kadanes3.cpp)
   * [Kelvin To Celsius](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/others/kelvin_to_celsius.cpp)
   * [Lfu Cache](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/others/lfu_cache.cpp)
+  * [Longest Substring Without Repeating Characters](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/others/longest_substring_without_repeating_characters.cpp)
   * [Lru Cache](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/others/lru_cache.cpp)
   * [Matrix Exponentiation](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/others/matrix_exponentiation.cpp)
   * [Palindrome Of Number](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/others/palindrome_of_number.cpp)
@@ -324,6 +325,7 @@
   * [Addition Rule](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/probability/addition_rule.cpp)
   * [Bayes Theorem](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/probability/bayes_theorem.cpp)
   * [Binomial Dist](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/probability/binomial_dist.cpp)
+  * [Exponential Dist](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/probability/exponential_dist.cpp)
   * [Geometric Dist](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/probability/geometric_dist.cpp)
   * [Poisson Dist](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/probability/poisson_dist.cpp)
   * [Windowed Median](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/probability/windowed_median.cpp)
@@ -338,6 +340,7 @@
   * [Sparse Table](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/range_queries/sparse_table.cpp)
 
 ## Search
+  * [Longest Increasing Subsequence Using Binary Search](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/search/Longest_Increasing_Subsequence_using_binary_search.cpp)
   * [Binary Search](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/search/binary_search.cpp)
   * [Exponential Search](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/search/exponential_search.cpp)
   * [Fibonacci Search](https://github.com/TheAlgorithms/C-Plus-Plus/blob/HEAD/search/fibonacci_search.cpp)

others/longest_substring_without_repeating_characters.cpp

@@ -0,0 +1,110 @@
+/**
+ * @file
+ * @brief Solution for Longest Substring Without Repeating Characters problem.
+ * @details
+ * Problem link: https://leetcode.com/problems/longest-substring-without-repeating-characters/description/
+ * 
+ * Intuition:
+ * 1) The intuition is straightforward and simple. We track the frequency of characters.
+ * 2) Since we can't use a string to track the longest substring without repeating characters efficiently (as removing a character from the front of a string isn't O(1)), we optimize the solution using a deque approach.
+ *
+ * Approach:
+ * 1) Initialize an unordered_map to track the frequency of characters.
+ * 2) Use a deque for pushing characters, and update the result deque (`res`) with the current deque (`temp`) 
+ *    whenever we find a longer substring.
+ * 3) Use a while loop to reduce the frequency from the front, incrementing `i`, 
+ *    and removing characters from the `temp` deque as we no longer need them.
+ * 4) Return `res.size()` as we are interested in the length of the longest substring.
+ * 
+ * Time Complexity: O(N)
+ * Space Complexity: O(N)
+ * 
+ * I hope this helps to understand.
+ * Thank you!
+ * @author [Ashish Kumar Sahoo](github.com/ashish5kmax)
+ **/
+
+#include <iostream>        // for IO Operations
+#include <unordered_map>   // for std::unordered_map
+#include <deque>           // for std::deque
+#include <string>          // for string class/string datatype which is taken as input
+#include <cassert>         // for assert
+
+/**
+ * @class Longest_Substring
+ * @brief Class that solves the Longest Substring Without Repeating Characters problem.
+ */
+class Longest_Substring {
+public:
+    /**
+     * @brief Function to find the length of the longest substring without repeating characters.
+     * @param s Input string.
+     * @return Length of the longest substring.
+     */
+    int lengthOfLongestSubstring(std::string s) {
+        // If the size of string is 1, then it will be the answer.
+        if (s.size() == 1) return 1;
+
+        // Map used to store the character frequency.
+        std::unordered_map<char, int> m;
+        int n = s.length();
+
+        // Deque to remove from back if repeating characters are present.
+        std::deque<char> temp;
+        std::deque<char> res;
+        int i, j;
+
+        // Sliding window approach using two pointers.
+        for (i = 0, j = 0; i < n && j < n;) {
+            m[s[j]]++;
+
+            // If repeating character found, update result and remove from the front.
+            if (m[s[j]] > 1) {
+                if (temp.size() > res.size()) {
+                    res = temp;
+                }
+
+                while (m[s[j]] > 1) {
+                    temp.pop_front();
+                    m[s[i]]--;
+                    i++;
+                }
+            }
+
+            // Add the current character to the deque.
+            temp.push_back(s[j]);
+            j++;
+        }
+
+        // Final check to update result.
+        if (temp.size() > res.size()) {
+            res = temp;
+        }
+
+        return res.size();  // Return the length of the longest substring.
+    }
+};
+
+/**
+ * @brief Self-test implementations
+ * @returns void
+ */
+static void tests() {
+    Longest_Substring soln;
+    assert(soln.lengthOfLongestSubstring("abcabcbb") == 3);
+    assert(soln.lengthOfLongestSubstring("bbbbb") == 1);
+    assert(soln.lengthOfLongestSubstring("pwwkew") == 3);
+    assert(soln.lengthOfLongestSubstring("") == 0); // Test case for empty string
+    assert(soln.lengthOfLongestSubstring("abcdef") == 6); // Test case for all unique characters
+    assert(soln.lengthOfLongestSubstring("a") == 1); // Single character
+    std::cout << "All test cases passed!" << std::endl;
+}
+
+/**
+ * @brief Main function.
+ * @return 0 on successful execution.
+ */
+int main() {
+    tests(); // run self-test implementations
+    return 0;
+}

probability/exponential_dist.cpp

@@ -0,0 +1,151 @@
+/**
+ * @file
+ * @brief [Exponential
+ * Distribution](https://en.wikipedia.org/wiki/Exponential_distribution)
+ *
+ * The exponential distribution is used to model
+ * events occuring between a Poisson process like radioactive decay.
+ *
+ * \f[P(x, \lambda) = \lambda e^{-\lambda x}\f]
+ *
+ * Summary of variables used:
+ * \f$\lambda\f$ : rate parameter
+ */
+
+#include <cassert>    // For assert
+#include <cmath>      // For std::pow
+#include <iostream>   // For I/O operation
+#include <stdexcept>  // For std::invalid_argument
+#include <string>     // For std::string
+
+/**
+ * @namespace probability
+ * @brief Probability algorithms
+ */
+namespace probability {
+/**
+ * @namespace exponential_dist
+ * @brief Functions for the [Exponential
+ * Distribution](https://en.wikipedia.org/wiki/Exponential_distribution)
+ * algorithm implementation
+ */
+namespace geometric_dist {
+/**
+ * @brief the expected value of the exponential distribution
+ * @returns \f[\mu = \frac{1}{\lambda}\f]
+ */
+double exponential_expected(double lambda) {
+    if (lambda <= 0) {
+        throw std::invalid_argument("lambda must be greater than 0");
+    }
+    return 1 / lambda;
+}
+
+/**
+ * @brief the variance of the exponential distribution
+ * @returns \f[\sigma^2 = \frac{1}{\lambda^2}\f]
+ */
+double exponential_var(double lambda) {
+    if (lambda <= 0) {
+        throw std::invalid_argument("lambda must be greater than 0");
+    }
+    return 1 / pow(lambda, 2);
+}
+
+/**
+ * @brief the standard deviation of the exponential distribution
+ * @returns \f[\sigma = \frac{1}{\lambda}\f]
+ */
+double exponential_std(double lambda) {
+    if (lambda <= 0) {
+        throw std::invalid_argument("lambda must be greater than 0");
+    }
+    return 1 / lambda;
+}
+}  // namespace geometric_dist
+}  // namespace probability
+
+/**
+ * @brief Self-test implementations
+ * @returns void
+ */
+static void test() {
+    double lambda_1 = 1;
+    double expected_1 = 1;
+    double var_1 = 1;
+    double std_1 = 1;
+
+    double lambda_2 = 2;
+    double expected_2 = 0.5;
+    double var_2 = 0.25;
+    double std_2 = 0.5;
+
+    double lambda_3 = 3;
+    double expected_3 = 0.333333;
+    double var_3 = 0.111111;
+    double std_3 = 0.333333;
+
+    double lambda_4 = 0;     // Test 0
+    double lambda_5 = -2.3;  // Test negative value
+
+    const float threshold = 1e-3f;
+
+    std::cout << "Test for lambda = 1 \n";
+    assert(
+        std::abs(expected_1 - probability::geometric_dist::exponential_expected(
+                                  lambda_1)) < threshold);
+    assert(std::abs(var_1 - probability::geometric_dist::exponential_var(
+                                lambda_1)) < threshold);
+    assert(std::abs(std_1 - probability::geometric_dist::exponential_std(
+                                lambda_1)) < threshold);
+    std::cout << "ALL TEST PASSED\n\n";
+
+    std::cout << "Test for lambda = 2 \n";
+    assert(
+        std::abs(expected_2 - probability::geometric_dist::exponential_expected(
+                                  lambda_2)) < threshold);
+    assert(std::abs(var_2 - probability::geometric_dist::exponential_var(
+                                lambda_2)) < threshold);
+    assert(std::abs(std_2 - probability::geometric_dist::exponential_std(
+                                lambda_2)) < threshold);
+    std::cout << "ALL TEST PASSED\n\n";
+
+    std::cout << "Test for lambda = 3 \n";
+    assert(
+        std::abs(expected_3 - probability::geometric_dist::exponential_expected(
+                                  lambda_3)) < threshold);
+    assert(std::abs(var_3 - probability::geometric_dist::exponential_var(
+                                lambda_3)) < threshold);
+    assert(std::abs(std_3 - probability::geometric_dist::exponential_std(
+                                lambda_3)) < threshold);
+    std::cout << "ALL TEST PASSED\n\n";
+
+    std::cout << "Test for lambda = 0 \n";
+    try {
+        probability::geometric_dist::exponential_expected(lambda_4);
+        probability::geometric_dist::exponential_var(lambda_4);
+        probability::geometric_dist::exponential_std(lambda_4);
+    } catch (std::invalid_argument& err) {
+        assert(std::string(err.what()) == "lambda must be greater than 0");
+    }
+    std::cout << "ALL TEST PASSED\n\n";
+
+    std::cout << "Test for lambda = -2.3 \n";
+    try {
+        probability::geometric_dist::exponential_expected(lambda_5);
+        probability::geometric_dist::exponential_var(lambda_5);
+        probability::geometric_dist::exponential_std(lambda_5);
+    } catch (std::invalid_argument& err) {
+        assert(std::string(err.what()) == "lambda must be greater than 0");
+    }
+    std::cout << "ALL TEST PASSED\n\n";
+}
+
+/**
+ * @brief Main function
+ * @return 0 on exit
+ */
+int main() {
+    test();  // Self test implementation
+    return 0;
+}