Method Crossword

examples/crossword.cpp:93–263

Actual model

  };
  /// Actual model
  Crossword(const SizeOptions& opt)
    : Script(opt),
      w(grids[opt.size()][0]), h(grids[opt.size()][1]),
      letters(*this,w*h,'a','z') {
    // Pointer into the grid specification (width and height already skipped)
    const int* g = &grids[opt.size()][2];

    // Matrix for letters
    Matrix<IntVarArray> ml(letters, w, h);

    // Set black fields to 0
    {
      IntVar z(*this,0,0);
      for (int n = *g++; n--; ) {
        int x=*g++, y=*g++;
        ml(x,y)=z;
      }
    }

    // Array of all words
    IntVarArgs allwords;

    switch (opt.model()) {
    case MODEL_ELEMENT:
      // While words of length w_l to process
      while (int w_l=*g++) {
        // Number of words of that length in the dictionary
        int n_w = dict.words(w_l);
        // Number of words of that length in the puzzle
        int n=*g++;
        
        if (n > n_w) {
          fail();
        } else {
          // Array of all words of length w_l
          IntVarArgs words(*this,n,0,n_w-1);
          allwords << words;
          
          // All words of same length must be different
          distinct(*this, words, opt.ipl());
          
          for (int d=0; d<w_l; d++) {
            // Array that maps words to a letter at a certain position (shared among all element constraints)
            IntSharedArray w2l(n_w);
            // Initialize word to letter map
            for (int i=n_w; i--; )
              w2l[i] = dict.word(w_l,i)[d];
            // Link word to letter variable
            for (int i=0; i<n; i++) {
              // Get (x,y) coordinate where word begins
              int x=g[3*i+0], y=g[3*i+1];
              // Whether word is horizontal
              bool h=(g[3*i+2] == 0);
              // Constrain the letters to the words' letters
              element(*this, w2l, words[i], h ? ml(x+d,y) : ml(x,y+d));
            }
          }
          // Skip word coordinates