row learns from table

.idea/cosets.iml

@@ -1,2 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<module classpath="CMake" type="CPP_MODULE" version="4" />

.idea/misc.xml

@@ -1,15 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="CMakeWorkspace" PROJECT_DIR="$PROJECT_DIR$" />
-  <component name="CidrRootsConfiguration">
-    <sourceRoots>
-      <file path="$PROJECT_DIR$/cosets/src" />
-    </sourceRoots>
-    <libraryRoots>
-      <file path="$PROJECT_DIR$/vendor" />
-    </libraryRoots>
-  </component>
-  <component name="JavaScriptSettings">
-    <option name="languageLevel" value="ES6" />
-  </component>
-</project>

.idea/modules.xml

@@ -1,8 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="ProjectModuleManager">
-    <modules>
-      <module fileurl="file://$PROJECT_DIR$/.idea/cosets.iml" filepath="$PROJECT_DIR$/.idea/cosets.iml" />
-    </modules>
-  </component>
-</project>

.idea/vcs.xml

@@ -1,6 +0,0 @@
-<?xml version="1.0" encoding="UTF-8"?>
-<project version="4">
-  <component name="VcsDirectoryMappings">
-    <mapping directory="$PROJECT_DIR$" vcs="Git" />
-  </component>
-</project>

cosets/src/tc.cpp

@@ -1,11 +1,13 @@
 #include <iostream>
 #include <vector>
 
+template<int N>
 struct Row;
 
 template<int N>
 struct Table;
 
+template<int N>
 struct Row {
    std::vector<int>::const_iterator l;
    std::vector<int>::const_iterator r;
@@ -15,10 +17,37 @@ struct Row {
 
    Row(const std::vector<int> &vec, int from, int to) {
       this->l = vec.begin();
-      this->r = vec.end();
+      this->r = vec.end() - 1;
       this->from = from;
       this->to = to;
    }
+
+   bool learn(Table<N> &table) {
+      if (r - l == 0) {
+         return false;
+      }
+
+      while (r - l > 0) {
+         int next = table.get(from, *l);
+         if (next < 0) break;
+         l++;
+         from = next;
+      }
+
+      while (r - l > 0) {
+         int next = table.rget(*r, to);
+         if (next < 0) break;
+         r--;
+         to = next;
+      }
+
+      if (r - l == 0) {
+         table.set(from, *l, to);
+         return true;
+      }
+
+      return false;
+   }
 };
 
 template<int N>
@@ -26,15 +55,52 @@ struct Table {
    std::vector<std::vector<int>> fwd;
    std::vector<std::vector<int>> rev;
 
+   Table() {
+      add_row();
+   }
+
    void add_row() {
-      fwd.push_back(std::vector<int>(N));
+      fwd.push_back(std::vector<int>(N, -1));
+      rev.push_back(std::vector<int>(N, -1));
+   }
+
+   int add_coset() {
+      for (int from = 0; from < size(); ++from) {
+         for (int gen = 0; gen < N; ++gen) {
+            if (get(from, gen) < 0) {
+               int to = size();
+               add_row();
+               set(from, gen, to);
+               return to;
+            }
+         }
+      }
+      return 0;
+   }
+
+   [[nodiscard]] unsigned size() const {
+      return fwd.size();
+   }
+
+   void set(int from, int gen, int to) {
+      fwd[from][gen] = to;
+      rev[to][gen] = from;
+   }
+
+   [[nodiscard]] int get(int from, int gen) const {
+      return fwd[from][gen];
+   }
+
+   [[nodiscard]] int rget(int gen, int to) const {
+      return rev[to][gen];
    }
 };
 
-std::ostream &operator<<(std::ostream &out, const Row &row) {
+template<int N>
+std::ostream &operator<<(std::ostream &out, const Row<N> &row) {
    out << "[ " << row.from << " | ";
    auto it = row.l;
-   while (it != row.r) {
+   while (row.r - it > 0) {
       out << *it << " ";
       it++;
    }
@@ -45,7 +111,7 @@ std::ostream &operator<<(std::ostream &out, const Row &row) {
 template<int N>
 std::ostream &operator<<(std::ostream &out, const Table<N> &table) {
    out << "[";
-   for (int j = 0; j < table.fwd.size(); ++j) {
+   for (unsigned j = 0; j < table.size(); ++j) {
       auto arr = table.fwd[j];
       out << "[";
       for (int i = 0; i < N; ++i) {
@@ -65,19 +131,33 @@ std::ostream &operator<<(std::ostream &out, const Table<N> &table) {
 }
 
 int main(int argc, char *argv[]) {
-   int gens = 2;
    std::vector<std::vector<int>> ids{
       {0, 0},
       {1, 1},
       {0, 1, 0, 1, 0, 1}
    };
 
+   Row<3> row(ids[2], 0, 0);
    Table<3> table;
+
    table.add_row();
    table.add_row();
    table.add_row();
-   table.add_row();
-   std::cout << table;
+
+   table.set(0, 0, 1);
+   table.set(1, 1, 2);
+
+   std::cout << table << std::endl;
+   std::cout << row << std::endl;
+
+   row.learn(table);
+   std::cout << row << std::endl;
+
+//   std::cout << table << std::endl;
+//   table.add_coset();
+//   std::cout << table << std::endl;
+//
+//   row.learn(table);
 
    return 0;
-}
+}