backtracking

window.cpp

@@ -71,10 +71,27 @@ Window::Window(QWidget *parent)
 
 void Window::solveButtonClicked()
 {
-    // std::array<Cell,81> start = m_cell;
-    std::list<Cell*> hist;
+    std::list<History *> hist;
+    bool end = false;
     srand(time(NULL));
     while (1)
+    {
+        if (end)
+        {
+            hist.back()->cell->un();
+            if (hist.back()->index.size() == 0)
+            {
+                hist.pop_back();
+                continue;
+            }
+            end = false;
+            int choiceNr = rand() % hist.back()->index.size();         // choose a random number;
+            hist.back()->cell->collapse(hist.back()->index[choiceNr]); // collapse cell with chosen number;
+            std::vector<int>::iterator it;
+            it = hist.back()->index.begin() + choiceNr;
+            hist.back()->index.erase(it);
+        }
+        else
         {
             std::vector<Cell *> b; // vector of cells with least entropy
             int minEtropy = 10;
@@ -101,26 +118,26 @@ void Window::solveButtonClicked()
                 qInfo("Solved!!");
                 return;
             }
-        else if(minEtropy ==0){
-            while (hist.size()>0)
+            else if (minEtropy == 0)
             {
-                hist.back()->un();
-                hist.pop_back();
-            }
-            return;
-            //solveButtonClicked();
+                qInfo("backtracking");
+                end = true;
+                continue;
             }
+
             int choiceCell = rand() % b.size();                  // choose a random cell
             int choiceNr = rand() % b[choiceCell]->index.size(); // choose a random number;
+            hist.push_back(new History(b[choiceCell], b[choiceCell]->index, choiceNr));
             b[choiceCell]->collapse(b[choiceCell]->index[choiceNr]); // collapse that random cell with chosen number;
-        hist.push_back(b[choiceCell]);
+        }
         repaint(); // draw cells again
         QThread::msleep(m_delay);
     }
     // qInfo("%d---:)");
 }
 
-void Window::setValue(int s){
+void Window::setValue(int s)
+{
     m_delay = s;
     return;
 }
\ No newline at end of file

window.h

@@ -11,6 +11,7 @@ class Window : public QWidget
     Q_OBJECT
 public:
     explicit Window(QWidget *parent = nullptr);
+
 private:
     QPushButton *m_buttonQuit;
     QPushButton *m_button;
@@ -19,6 +20,21 @@ private:
     QSlider *m_slider;
     std::array<Cell, 81> m_cell;
     int m_delay = 300;
+    struct History
+    {
+        Cell *cell;
+        std::vector<int> index;
+        History(Cell *c, std::vector<int> in,int choice)
+        {
+            cell = c;
+            for(int i=0;i<in.size();i++){
+                if(i == choice)
+                    continue;
+                index.push_back(in[i]);
+            }
+        }
+    };
+
 signals:
     void counterReached();
 private slots: