CYK

.github/workflows/Test.yml

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+name: BuildTest
+
+on:
+  push:
+    branches: [ master, CYK ]
+  pull_request:
+    branches: [ master, CYK ]
+jobs:
+  Build-ubuntu:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1
+      - name: "Build and run tests"
+        run : |
+          git clone https://github.com/google/googletest
+          cd googletest
+          cd googletest
+          cmake ..
+          make
+          sudo make install
+          cd ../../
+          cmake tests
+          make
+          ./Test

CYK.cpp

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+#include "CYK.hpp"
+
+bool CFG::isCNF() {
+  bool ok = true;
+  for (auto rule : P) {
+    if (!ok) {
+      break;
+    }
+    if (!N.contains(rule.first)) {
+      ok = false;
+      break;
+    }
+    for (auto rpart : rule.second) {
+      if (rpart.size() > 2) {
+        ok = false;
+        break;
+      }
+      if (rpart.size() == 1 && (!alp.contains(rpart[0]) || (rpart == "1" && rule.first != S))) {
+        ok = false;
+        break;
+      }
+      if (rpart.size() == 2 && (!N.contains(rpart[0]) || !N.contains(rpart[1]))) {
+        ok = false;
+        break;
+      }
+    }
+  }
+  return ok;
+}
+
+void CFG::Scan() {
+  cout << "Enter size of sigma: ";
+  size_t sz = 0;
+  char c = 0;
+  string s;
+  cin >> sz;
+  cout << endl << "Enter symbols:" << endl;
+  for (size_t i = 0; i < sz; ++i) {
+    cin >> c;
+    alp.insert(c);
+  }
+  cout << endl << "Enter size of N: ";
+  cin >> sz;
+  cout << endl << "Enter symbols:" << endl;
+  for (size_t i = 0; i < sz; ++i) {
+    cin >> c;
+    N.insert(c);
+  }
+  cout << endl << "Enter start symbol: ";
+  cin >> S;
+  if (!N.contains(S)) {
+    throw runtime_error("N does not contain start symbol!!!");
+  }
+  cout << endl << "Enter size of set of prod rules: ";
+  cin >> sz;
+  for (size_t i = 0; i < sz; ++i) {
+    cin >> c;
+    if (!N.contains(c)) {
+      throw runtime_error("Context free grammar can not contain terminal in left part of the rule!!!");
+    }
+    cout << "right part: ";
+    cin >> s;
+    cout << endl;
+    P[c].insert(s);
+  }
+}
+
+bool CFG::Recognize(const string &w) {
+  if (!isCNF()) {
+    throw runtime_error("Not in CNF!!!");
+  }
+  if (P[S].contains("1") && w.size() == 0) {
+    return true;
+  } else if (w.size() == 0 && !P[S].contains("1")) {
+    return false;
+  }
+  return CYK(w);
+}
+
+bool CFG::CYK(const string &w) {
+  map<char, vector<vector<bool>>> tb;
+  for (char A : N) {
+    tb[A] = vector<vector<bool>>(w.size() + 1, vector<bool>(w.size() + 1, false));
+    for (size_t i = 0; i <= w.size(); ++i) {
+      for (size_t j = 0; j <= w.size(); ++j) {
+        if (j == i + 1) {
+          for (auto rule_rp : P[A]) {
+            if (rule_rp.size() == 1 && rule_rp[0] == w[i]) {
+              tb[A][i][j] = true;
+            }
+          }
+        }
+      }
+    }
+  }
+  for (size_t l = 2; l <= w.size(); ++l) {
+    for (size_t i = 0; i <= w.size() - l; ++i) {
+      size_t j = i + l;
+      for (size_t k = i + 1; k <= j - 1; ++k) {
+        for (auto A : N) {
+          for (auto rule_rp : P[A]) {
+            if (rule_rp.size() == 2 && tb[rule_rp[0]][i][k] && tb[rule_rp[1]][k][j]) {
+              tb[A][i][j] = true;
+            }
+          }
+        }
+      }
+    }
+  }
+  return tb[S][0][w.size()];
+}

CYK.hpp

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+#include <iostream>
+#include <vector>
+#include <string>
+#include <set>
+#include <map>
+
+using namespace std;
+
+class CFG {
+public:
+    set<char> alp;
+    set<char> N;
+    char S;
+    map<char, set<string>> P;
+
+    CFG() = default;
+
+    void Scan();
+
+    bool isCNF();
+
+    bool Recognize(const string& w);
+
+    bool CYK(const string& w);
+};

README.md

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+In: Context-free grammar in Chomsky normal form. Word
+
+Out: Indicator of the belonging of the word to the language

tests/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.5)
+
+project(Test)
+set(CMAKE_CXX_STANDARD 20)
+
+find_package(Threads REQUIRED)
+find_package(GTest REQUIRED)
+
+add_executable(${PROJECT_NAME} "main.cpp" "RecognizeTestCase.hpp" "RecognizeTestCase.cpp" "../CYK.cpp")
+
+target_include_directories(${PROJECT_NAME}
+	PRIVATE
+	${GTEST_INCLUDE_DIR})
+
+target_link_libraries(${PROJECT_NAME}
+	PRIVATE
+	GTest::GTest
+	Threads::Threads)