Coin change

coin-change.dot

digraph {

  label="Counting change: 100 cents in quarters and dime";

  1 [label="100, (10, 25)"];

  2 [label="100, 25"];
  3 [label="90, (10, 25)"];

  4 [label="100, -"];
  5 [label="75, 25"];
  6 [label="90, 25"];
  7 [label="80, (10, 25)"];

  a [label="0", shape=box];
  b [label="1", shape=box];
  c [label="0", shape=box];
  d [label="2", shape=box];

  e [label="Three ways in total", shape=box];

  1 -> 2;
  1 -> 3;

  2 -> 4;
  2 -> 5;
  3 -> 6;
  3 -> 7;

  4 -> a;
  5 -> b [style=dotted];
  6 -> c [style=dotted];
  7 -> d [style=dotted];
  
  a -> e;
  b -> e;
  c -> e;
  d -> e;

}