wildcard_matching.cpp

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#include <cassert>   
#include <cstdint>
#include <iostream>  
#include <vector>    
 
namespace backtracking {
namespace wildcard_matching {
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
 
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;
}
 
int main() {
    test();  // run self-test implementations
    return 0;
}