I enjoy the game King of Thieves and one aspect I'm always trying to improve is picking the locks. I know I can't cheat probability but it sure is fun trying. You have X amount of locks and you try opening them one-by-one. My current strategy is to just start from the first lock and work my way through to the end. The following JavaScript will a…

try-to-cheat-probability-lol.js

(function() {
    var numLocks = 8;
    var iterations = 1000;

    function random(min, max) {
        "use strict";
        return Math.round(Math.random() * (max - min) + min);
    }

    function buildLocksArray() {
        "use strict";
        var locks = [];
        var r = random(0, numLocks-1);
        for (var i=0; i<numLocks; i++) {
            if (i === r) {
                locks.push('y');
            } else {
                locks.push('n');
            }
        }
        return locks;
    }

    function buildRandomGuessOrder() {
        var chosen = [];
        var guessOrder = [];
        for (var i=0; i<numLocks; i++) {
            var r = random(0, numLocks-1);
            while (chosen.indexOf(r) > -1) {
                r = random(0, numLocks-1);
            }
            guessOrder.push(r);
            chosen.push(r);
        }
        return guessOrder;
    }

    function guess(guessRandom, guessOrder) {
        var guesses = [];
        for (var i=0; i<iterations; i++) {
            var locksArray = buildLocksArray();

            var c = 1;
            if (guessRandom) {
                guessOrder = buildRandomGuessOrder();
            }
            for (var k in guessOrder) {
                if (locksArray[guessOrder[k]] === 'y') {
                    guesses.push(c);
                    break;
                }
                c++;
            }
        }
        return guesses;
    }

    print(Math.round(guess(false, [0, 1, 2, 3, 4, 5, 6, 7])
            .reduce(function(x, y) { return x + y; }) / iterations));

    print(Math.round(guess(false, [0, 1, 2, 7, 3, 4, 5, 6])
            .reduce(function(x, y) { return x + y; }) / iterations));

    print(Math.round(guess(true)
            .reduce(function(x, y) { return x + y; }) / iterations));

})();