2KeysKeyboard.js

var helper = function(current, last, target) {
    if (current == target) {
        return 0;
    } else if (current > target) {
        return Infinity;
    }
    
    let option1 = last != current ? helper(current, current, target) + 1 : Infinity;
    let option2 = last != 0 ? helper(current + last, last, target) + 1 : Infinity;
    if (option1 < option2) {
        return option1;
    } else {
        return option2;
    }
};

/**
 * @param {number} n
 * @return {number}
 */
var minSteps = function(n) {
    return helper(1, 0, n);
};