Greplin Solutions

solutions.js

// one
function palindrome(text) {
    var longest = '';
    
    for (var i = 0; i < text.length; i++) {
        var charOne = text.charAt(i);
        
        for (var j = text.length-1; j > i; j--) {
            var charTwo = text.charAt(j);
            
            if (charOne != charTwo) { continue; }
            
            var k = i;
            var l = j;
            var palindrome = true;
            while (k < l) {
                if (text.charAt(k) == text.charAt(l)) {
                    k++;
                    l--;
                    continue;
                }
                palindrome = false;
                break;
            }
            
            var length = j-i;
            if (palindrome == true && length > longest.length) {
                longest = text.slice(i, j+1);
            }
        }
    }
    
    return longest;
}

// two
function isPrime(n) {
    if (n <= 1)   { return false; }
    if (n == 2)   { return true; }
    if (n%2 == 0) { return false; }
    
    var sqrt = Math.sqrt(n);
    
    for (var i = 3; i <= sqrt; i += 2) {
        if (n % i == 0) { return false; }
    }
    
    return true;
}
function nextPrime(n) {
    if (n < 1) { return 1; }
    
    while (n++) {
        if (isPrime(n) == true) { return n; }
    }
}
function factorize(n) {
    var factors = [];
    
    if (n < 4) { return factors; }
    
    var prime  = nextPrime(1);
    var remain = n;
    while(remain > prime && isPrime(remain) == false) {
        if (remain % prime == 0) { factors.push(prime); }
        
        while(remain > prime && remain % prime == 0) {
            remain = remain/prime;
        }
        
        prime = nextPrime(prime);
    }
    
    if (factors.indexOf(remain) < 0) { factors.push(remain); }
    
    return factors;
}
var cache = {};
function fib(n) {
    if (n < 4) { return 1; }
    if (cache[n]) { return cache[n]; }
    
    cache[n] = fib(n-1) + fib(n-2);
    
    return cache[n];
}
function fast_fib(n) {
    if (n < 3) { return 1; }
    
    var lastOne = 1;
    var lastTwo = 1;
    var sum     = lastOne + lastTwo;
    
    for (var i = 3; i <= n; i++) {
        var sum = lastOne + lastTwo;
        lastTwo = lastOne;
        lastOne = sum;
    }
    
    return sum;
}
function fibPrime(n) {
    var i = 1;
    var f = fib(i);
    
    while (f <= n || isPrime(f) == false) {
        i++;
        f = fib(i);
    }
    
    return f;
}
function sum(array) {
    var sum = 0;
    
    for (var i = 0; i < array.length; i++) {
        sum += array[i];
    }
    
    return sum;
}

// three
function sets(array) {
    var cnt = 0;
    var len = 1 << array.length;
    
    for (var i = 0; i < len; i++) {
        var pos = array.length - 1;
        var bitmask = i;
        
        var subset = [];
        while(bitmask > 0) {
            if((bitmask & 1) == 1) {
                subset.push(array[pos]);
            }
            
            bitmask >>= 1;
            pos--;
        }
        
        if (subset.length < 1) { continue; }
        
        subset.sort(function(a,b) { return a==b ? 0 : a-b; });
        var max = subset[subset.length-1];
        
        var sum = 0;
        for (var j = 0; j < subset.length-1; j++) {
            sum += subset[j];
            if (sum > max) { continue; }
        }
        
        if (sum == max) {
            cnt++;
        }
    }
    
    return cnt;
}

var text = 'FourscoreandsevenyearsagoourfaathersbroughtforthonthiscontainentanewnationconceivedinzLibertyanddedicatedtothepropositionthatallmenarecreatedequalNowweareengagedinagreahtcivilwartestingwhetherthatnaptionoranynartionsoconceivedandsodedicatedcanlongendureWeareqmetonagreatbattlefiemldoftzhatwarWehavecometodedicpateaportionofthatfieldasafinalrestingplaceforthosewhoheregavetheirlivesthatthatnationmightliveItisaltogetherfangandproperthatweshoulddothisButinalargersensewecannotdedicatewecannotconsecratewecannothallowthisgroundThebravelmenlivinganddeadwhostruggledherehaveconsecrateditfaraboveourpoorponwertoaddordetractTgheworldadswfilllittlenotlenorlongrememberwhatwesayherebutitcanneverforgetwhattheydidhereItisforusthelivingrathertobededicatedheretotheulnfinishedworkwhichtheywhofoughtherehavethusfarsonoblyadvancedItisratherforustobeherededicatedtothegreattdafskremainingbeforeusthatfromthesehonoreddeadwetakeincreaseddevotiontothatcauseforwhichtheygavethelastpfullmeasureofdevotionthatweherehighlyresolvethatthesedeadshallnothavediedinvainthatthisnationunsderGodshallhaveanewbirthoffreedomandthatgovernmentofthepeoplebythepeopleforthepeopleshallnotperishfromtheearth';
console.log(palindrome(text));

console.log(sum(factorize(fibPrime(217000)+1)));

var array = [3, 4, 9, 14, 15, 19, 28, 37, 47, 50, 54, 56, 59, 61, 70, 73, 78, 81, 92, 95, 97, 99];
console.log(sets(array));