Towers of Hanoi - non-recursive

towers.js

/*
  Towers of Hanoi
  (non-recursive solution)
  
  https://blog.svpino.com/2015/06/07/programming-challenge-towers-of-hanoi
*/

function solveHanoi(discs){
  var towers = {a:[],b:[],c:[]};

  function view (){
    var t = JSON.parse(JSON.stringify(towers));
    var x = "", y;
    for(var i = 0; i <= discs-1;i++){
      y = "";
      for(var j in towers){
        y += (t[j].pop() || " ") + " | ";
      }
      y += "\n";
      x = y + x;
    }
    return "\n"+x;
  }
  
  // Disc size 1-discs, 1 = smallest
  var k = discs+1;
  while(k-->1){towers.a.unshift(k);}
  console.log("START",view());

  // First move
  var move = 1, movedone, smallest = ["a"];
  smallest.unshift(discs%2 ? "c" : "b");
  towers[smallest[0]].unshift(towers.a.shift());
  console.log("MOVE " + move,view());

  // Rest moves
  while(towers.c.length < discs){
    move++;
    movedone = false;
    for(var i in towers){
      if(movedone){break;}
      if(towers[i][0]){
        for(var j in towers){
          if(i==j || towers[i][0]==1){continue;}
          if(!towers[j][0] || towers[j][0]>towers[i][0]){
            towers[j].unshift(towers[i].shift());
            console.log("MOVE " + move,view());
            movedone = true;
          }
        }
      }
    }
    move++;
    smallest = smallest.slice(0,2);
    for(var i in towers){
      if(smallest.indexOf(i)<0){
        towers[i].unshift(towers[smallest[0]].shift());
        smallest.unshift(i);
        console.log("MOVE " + move,view());
        break;
      }
    }
  }
}