RosettaCodeData/Task/100-doors/JavaScript/100-doors-6.js

45 lines
1.1 KiB
JavaScript

(function (n) {
'use strict';
return range(1, 100)
.filter(function (x) {
return integerFactors(x)
.length % 2;
});
function integerFactors(n) {
var rRoot = Math.sqrt(n),
intRoot = Math.floor(rRoot),
lows = range(1, intRoot)
.filter(function (x) {
return (n % x) === 0;
});
// for perfect squares, we can drop the head of the 'highs' list
return lows.concat(lows.map(function (x) {
return n / x;
})
.reverse()
.slice((rRoot === intRoot) | 0));
}
// range(intFrom, intTo, optional intStep)
// Int -> Int -> Maybe Int -> [Int]
function range(m, n, delta) {
var d = delta || 1,
blnUp = n > m,
lng = Math.floor((blnUp ? n - m : m - n) / d) + 1,
a = Array(lng),
i = lng;
if (blnUp)
while (i--) a[i] = (d * i) + m;
else
while (i--) a[i] = m - (d * i);
return a;
}
})(100);