Watermelons in the Desert You live in a desert oasis and grow miniature watermelons that are worth a great deal of money, if you can get them to the market 15 kilometers away across the desert. Your harvest this year is 45 melons, but you have no way to get them to the market, except to carry them across the desert. You have a backpack that hold…

melons-in-the-desert.js

var dropped = [45, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
var log = [];
var result = 15;
var pos = 0;
var held = 0;
var error = false;
var attempt = 0;
var done = false;
var doerrors = false;// set to true for error messages
function reset(){
  dropped = [45, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0];
  log = [];
  result = 15;
  pos = 0;
  held = 0;
  error = false;
  attempt = 0;
  if(!doerrors){
    console.error = function (n){}
  };
}
function pickup(num){
  if(num > dropped[pos]){
    console.error("You cannot pick up "+ num + " melons as there are only " + dropped[pos] + " at position "+ pos);
    error = true;
    return false;
  };
  if((held + num) > 15){
    console.error("You cannot pick up "+ num + " melons as you are already holding " + held + " melons");
    error = true;
    return false;
  };
  held += num;
  dropped[pos] -= num;
  log.push("picked up "+ num + " melons");
  attempt++;
  if(attempt > 100){
    error = true;
  };
  if(held === 0 && dropped[0] === 0 && pos === 0){
    done = true;
    result = dropped[15];
  };
}
function drop(num){
  if(num > held){
    console.error("You cannot drop "+ num + " melons as you only have " + held + " melons");
    error = true;
    return false;
  };
  held -= num;
  dropped[pos] += num;
  log.push("dropped " + num + " melons");
  attempt++;
  if(attempt > 100){
    error = true;
  };
  if(held === 0 && dropped[0] === 0 && pos === 0){
    done = true;
    result = dropped[15];
  };
}
function move(num){
  if((pos + num) > 15 || (pos + num) < 0){
    console.error("You cannot move to position "+ (pos + num) + " as you are at position "+ pos + " and cannot move out of the world");
    error = true;
    return false;
  };
  if((held - num) < 1){
    console.error("You cannot move as you don't have any melons");
    error = true;
    return false;
  };
  held -= Math.abs(num);
  pos += num;
  log.push("moved " + Math.abs(num) + " miles to position " + pos + " and ate " + Math.abs(num) + " melons");
  attempt++;
  if(attempt > 100){
    error = true;
  };
  if(held === 0 && dropped[0] === 0 && pos === 0){
    done = true;
    result = dropped[15];
  };
}

solution-finder.js

// requires above file
var record = 15;
var recordLog = [];
var lt = -1;
function random(min, max) {
  return min + Math.floor(Math.random() * Math.floor(max));
}
function start(interval){
  reset();
  while(!error && !done){
    var mt = random(0, 3);
    if(mt === 0){
      pickup(random(1, 15));
    }else if(mt === 1){
      drop(random(1, held));
    }else if(mt === 2){
      move(random(1, (15 - pos)));
    }else if(mt === 3){
      move((random(1, (0 + pos))) * -1);
    };
  };
  if(done){
    if(result > record){
      record = result;
      recordlog = [];
      for(var i = 0;i < log.length;i++){
        recordLog.push(log[i]);
      };
      console.log("new record found: " + record);
    };
  };
  lt = setTimeout(function (){start(interval || 500)}, (interval || 500));
}
function stop(){
  clearTimeout(lt);
};