A script to find solutions to Calculator: The Game

calcgame.js

// This is a script to find a solution to Calculator: The Game
// https://play.google.com/store/apps/details?id=com.sm.calculateme

function add(a) {
  return {
    apply: function(b) {
      return a + b;
    },
    info: 'add ' + a
  }
}
function multiply(a) {
  return {
    apply: function(b) {
      return a * b;
    },
    info: 'mult ' + a
  }
}
function concat(a) {
  return {
    apply: function(b) {
      return parseInt(b.toString() + a.toString())
    },
    info: 'concat ' + a
  }
}
function replace(a, b) {
  return {
    apply: function(n) {
      return parseInt(n.toString().replace(new RegExp(a, 'g'), b))
    },
    info: 'replace ' + a + ' with ' + b
  }
}
let shift = {
  apply: function(a) {
    return Math.floor(a / 10)
  },
  info: 'shift'
}
let square = {
  apply: function(a) {
    return a * a;
  },
  info: 'squared'
}

let flip = multiply(-1);

let reverse = {
  apply: function(a) {
    return parseInt(a.toString().split('').reverse().join(''))
  },
  info: 'reverse'
}

// simply bruteforce the solution, the complexity is actions.length^moves, the number of actions is bounded by 6
function bruteforce(start, goal, moves, actions) {
  while (true) {
    let number = start;
    let solution = [];
    for (let i = 0; i < moves; i++) {
      let action = actions[Math.floor(actions.length * Math.random())];
      number = action.apply(number);
      solution.push(action.info);
      if (number === goal) return solution;
    }
  }
}

// Level 62
// add the possible actions here
let actions = [concat(10), multiply(4), add(5), reverse];
console.log(bruteforce(0, 102, 4, actions))