find-rabbit.js

const day = ([...holes]) => {
  const currentHole = holes.indexOf(1);

  holes[currentHole] = 0;

  if (currentHole === 0) {
    holes[1] = 1;
  } else if (currentHole === 4) {
    holes[3] = 1;
  } else {
    holes[currentHole + [-1, 1][getRandomInt(2)]] = 1;
  }
  return holes;
};

const getRandomInt = max => {
  return Math.floor(Math.random() * Math.floor(max));
};

const checkHole = (holes, hole) => {
  return !!holes[hole];
};

const getHoles = () => {
  const holes = [0, 0, 0, 0, 0];
  holes[getRandomInt(5)] = 1;
  return holes;
};

const maxDays = 6;

const checkAlg = alg => {
  let daysPassed = 0;
  let success = false;
  let currentHoles = getHoles();

  for (let i = 0; i < maxDays; i++) {
    daysPassed++;
    const check = checkHole(currentHoles, alg[i]);
    if (check) {
      success = true;
      break;
    }
    currentHoles = day(currentHoles);
  }

  return {
    days: daysPassed,
    success: success,
    alg: alg
  };
};

const tryAlg = alg => {
  const attemptsCount = 1000;

  const results = {
    count: attemptsCount,
    successRate: 0.0,
    successCount: 0,
    days: [],
    daysAvg: 0
  };

  for (let i = 0; i < attemptsCount; i++) {
    const result = checkAlg(alg);

    if (result.success) {
      results.successCount += 1;
      results.days.push(result.days);
    }
  }

  results.daysAvg =
    results.days.reduce((a, b) => a + b, 0) / results.days.length;
  results.successRate = results.successCount / results.count;

  console.log(
    `rate: ${results.successRate.toFixed(2)} days: ${results.daysAvg.toFixed(
      2
    )} ${alg}`
  );
  return results;
};

const mutate = ([...alg]) => {
  const randomStep = getRandomInt(alg.length);
  const oldValue = alg[randomStep];
  let newValue = getRandomInt(5);

  while (oldValue === newValue) {
    newValue = getRandomInt(5);
  }

  alg[randomStep] = newValue;

  return alg;
};

const start = () => {
  let alg = [];
  for (let i = 0; i < maxDays; i++) {
    alg[i] = getRandomInt(5);
  }

  let couner = 0;
  let results = tryAlg(alg);
  while (results.successRate !== 1.0) {
    alg = mutate(alg);
    results = tryAlg(alg);
    console.log(++couner, results.successRate);
  }

  console.log("Alg done!");
  console.log(alg);
};

start();