Merge branch 'master' into backtracking_doc_improvements

Author: Panquesito7

DIRECTORY.md

@@ -11,6 +11,7 @@
   * [Subarray Sum](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/backtracking/subarray_sum.cpp)
   * [Subset Sum](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/backtracking/subset_sum.cpp)
   * [Sudoku Solve](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/backtracking/sudoku_solve.cpp)
+  * [Wildcard Matching](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/backtracking/wildcard_matching.cpp)
 
 ## Bit Manipulation
   * [Count Of Set Bits](https://github.com/TheAlgorithms/C-Plus-Plus/blob/master/bit_manipulation/count_of_set_bits.cpp)

backtracking/wildcard_matching.cpp

@@ -0,0 +1,155 @@
+/**
+ * @file
+ * @brief Implementation of the [Wildcard
+ * Matching](https://www.geeksforgeeks.org/wildcard-pattern-matching/) problem.
+ * @details
+ * Given a matching string and a pattern, implement wildcard pattern
+ * matching with support for `?` and `*`. `?` matches any single character.
+ * `*` matches any sequence of characters (including the empty sequence).
+ * The matching should cover the entire matching string (not partial). The task
+ * is to determine if the pattern matches with the matching string
+ * @author [Swastika Gupta](https://github.com/Swastyy)
+ */
+
+#include <cassert>   /// for assert
+#include <iostream>  /// for IO operations
+#include <vector>    /// for std::vector
+
+/**
+ * @namespace backtracking
+ * @brief Backtracking algorithms
+ */
+namespace backtracking {
+/**
+ * @namespace wildcard_matching
+ * @brief Functions for the [Wildcard
+ * Matching](https://www.geeksforgeeks.org/wildcard-pattern-matching/) problem.
+ */
+namespace wildcard_matching {
+/**
+ * @brief The main function implements if pattern can be matched with given
+ * string
+ * @param s is the given matching string
+ * @param p is the given pattern
+ * @param pos1 is the starting index
+ * @param pos2 is the last index
+ * @returns 1 if pattern matches with matching string otherwise 0
+ */
+std::vector<std::vector<int64_t>> dpTable(1000, std::vector<int64_t>(1000, -1));
+bool wildcard_matching(std::string s, std::string p, uint32_t pos1,
+                       uint32_t pos2) {
+    uint32_t n = s.length();
+    uint32_t m = p.length();
+    // matching is successfull if both strings are done
+    if (pos1 == n && pos2 == m) {
+        return true;
+    }
+
+    // matching is unsuccessfull if pattern is not finished but matching string
+    // is
+    if (pos1 != n && pos2 == m) {
+        return false;
+    }
+
+    // all the remaining characters of patterns must be * inorder to match with
+    // finished string
+    if (pos1 == n && pos2 != m) {
+        while (pos2 < m && p[pos2] == '*') {
+            pos2++;
+        }
+
+        return pos2 == m;
+    }
+
+    // if already calculted for these positions
+    if (dpTable[pos1][pos2] != -1) {
+        return dpTable[pos1][pos2];
+    }
+
+    // if the characters are same just go ahead in both the string
+    if (s[pos1] == p[pos2]) {
+        return dpTable[pos1][pos2] =
+                   wildcard_matching(s, p, pos1 + 1, pos2 + 1);
+    }
+
+    else {
+        // can only single character
+        if (p[pos2] == '?') {
+            return dpTable[pos1][pos2] =
+                       wildcard_matching(s, p, pos1 + 1, pos2 + 1);
+        }
+        // have choice either to match one or more charcters
+        else if (p[pos2] == '*') {
+            return dpTable[pos1][pos2] =
+                       wildcard_matching(s, p, pos1, pos2 + 1) ||
+                       wildcard_matching(s, p, pos1 + 1, pos2);
+        }
+        // not possible to match
+        else {
+            return dpTable[pos1][pos2] = 0;
+        }
+    }
+}
+
+}  // namespace wildcard_matching
+}  // namespace backtracking
+
+/**
+ * @brief Self-test implementations
+ * @returns void
+ */
+static void test() {
+    // 1st test
+    std::cout << "1st test ";
+    std::string matching1 = "baaabab";
+    std::string pattern1 = "*****ba*****ab";
+    assert(backtracking::wildcard_matching::wildcard_matching(matching1,
+                                                              pattern1, 0, 0) ==
+           1);  // here the pattern matches with given string
+    std::cout << "passed" << std::endl;
+
+    // 2nd test
+    std::cout << "2nd test ";
+    std::string matching2 = "baaabab";
+    std::string pattern2 = "ba*****ab";
+    assert(backtracking::wildcard_matching::wildcard_matching(matching2,
+                                                              pattern2, 0, 0) ==
+           1);  // here the pattern matches with given string
+    std::cout << "passed" << std::endl;
+
+    // 3rd test
+    std::cout << "3rd test ";
+    std::string matching3 = "baaabab";
+    std::string pattern3 = "ba*ab";
+    assert(backtracking::wildcard_matching::wildcard_matching(matching3,
+                                                              pattern3, 0, 0) ==
+           1);  // here the pattern matches with given string
+    std::cout << "passed" << std::endl;
+
+    // 4th test
+    std::cout << "4th test ";
+    std::string matching4 = "baaabab";
+    std::string pattern4 = "a*ab";
+    assert(backtracking::wildcard_matching::wildcard_matching(matching4,
+                                                              pattern4, 0, 0) ==
+           1);  // here the pattern matches with given string
+    std::cout << "passed" << std::endl;
+
+    // 5th test
+    std::cout << "5th test ";
+    std::string matching5 = "baaabab";
+    std::string pattern5 = "aa?ab";
+    assert(backtracking::wildcard_matching::wildcard_matching(matching5,
+                                                              pattern5, 0, 0) ==
+           1);  // here the pattern matches with given string
+    std::cout << "passed" << std::endl;
+}
+
+/**
+ * @brief Main function
+ * @returns 0 on exit
+ */
+int main() {
+    test();  // run self-test implementations
+    return 0;
+}