samples/alpha-mj-exp/Parentheses.mj

   1 program Parentheses
   2 {
   3     // generate all possibilities of n pairs of parentheses
   4     // so that they are valid (open - closed)
   5
   6     void parentheses(char[] solution, int pos, int left, int right, int num)
   7     int i;
   8     {
   9         if (right == num) {
  10             i = 0;
  11             while (i < len(solution)) {
  12                 print(solution[i]);
  13                 print(' ');
  14                 i++;
  15             }
  16             print('\n');
  17         }
  18         if (left < num) {
  19             solution[pos] = '(';
  20             parentheses(solution, pos+1, left+1, right, num);
  21         }
  22         if (left > right) {
  23             solution[pos] = ')';
  24             parentheses(solution, pos+1, left, right+1, num);
  25         }
  26     }
  27
  28     void pars(char[] sln, int num) {
  29         if (num > 0) {
  30             parentheses(sln, 0, 0, 0, num);
  31         }
  32     }
  33
  34     void main()
  35     int i, dimension;
  36     char[] solution;
  37     {
  38         print('d');
  39         print('?');
  40         read(dimension);
  41         solution = new char[2*dimension];
  42         pars(solution, dimension);
  43     }
  44 }