tasks a-s

Task/Prime-decomposition/JavaScript/prime-decomposition-2.js

@@ -0,0 +1,41 @@
+function run_factorize(n) {
+	if (n <= 3)
+			return [n];
+
+	var ans = [];
+	var done = false;
+	while (!done)
+	{
+		if (n%2 === 0){
+				ans.push(2);
+				n /= 2;
+				continue;
+		}
+		if (n%3 === 0){
+				ans.push(3);
+				n /= 3;
+				continue;
+		}
+		if ( n === 1)
+			return ans;
+		var sr = Math.sqrt(n);
+		done = true;
+		// try to divide the checked number by all numbers till its square root.
+		for (var i=6; i<=sr; i+=6){
+				if (n%(i-1) === 0){ // is n divisible by i-1?
+						ans.push( (i-1) );
+						n /= (i-1);
+						done = false;
+						break;
+				}
+				if (n%(i+1) === 0){ // is n divisible by i+1?
+						ans.push( (i+1) );
+						n /= (i+1);
+						done = false;
+						break;
+				}
+		}
+	}
+	ans.push( n );
+	return ans;
+}