Data commit

Task/Prime-decomposition/JavaScript/prime-decomposition-1.js

@@ -0,0 +1,39 @@
+function run_factorize(input, output) {
+    var n = new BigInteger(input.value, 10);
+    var TWO = new BigInteger("2", 10);
+    var divisor = new BigInteger("3", 10);
+    var prod = false;
+
+    if (n.compareTo(TWO) < 0)
+        return;
+
+    output.value = "";
+
+    while (true) {
+        var qr = n.divideAndRemainder(TWO);
+        if (qr[1].equals(BigInteger.ZERO)) {
+            if (prod)
+                output.value += "*";
+            else
+                prod = true;
+            output.value += "2";
+            n = qr[0];
+        }
+        else
+            break;
+    }
+
+    while (!n.equals(BigInteger.ONE)) {
+        var qr = n.divideAndRemainder(divisor);
+        if (qr[1].equals(BigInteger.ZERO)) {
+            if (prod)
+                output.value += "*";
+            else
+                prod = true;
+            output.value += divisor;
+            n = qr[0];
+        }
+        else
+            divisor = divisor.add(TWO);
+    }
+}

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

@@ -0,0 +1,40 @@
+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 + 6); 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;
+}

Task/Prime-decomposition/JavaScript/prime-decomposition-3.js

@@ -0,0 +1,14 @@
+function factors(n) {
+  if (!n || n < 2)
+    return [];
+
+  var f = [];
+  for (var i = 2; i <= n; i++){
+    while (n % i === 0){
+      f.push(i);
+      n /= i;
+    }
+  }
+
+  return f;
+};

Task/Prime-decomposition/JavaScript/prime-decomposition-4.js

@@ -0,0 +1,48 @@
+/// <reference path="PrimeFactors.js" />
+
+describe("Prime Factors", function() {
+  it("Given nothing, empty is returned", function() {
+    expect(factors()).toEqual([]);
+  });
+
+  it("Given 1, empty is returned", function() {
+    expect(factors(1)).toEqual([]);
+  });
+
+  it("Given 2, 2 is returned", function() {
+    expect(factors(2)).toEqual([2]);
+  });
+
+  it("Given 3, 3 is returned", function() {
+    expect(factors(3)).toEqual([3]);
+  });
+
+  it("Given 4, 2 and 2 is returned", function() {
+    expect(factors(4)).toEqual([2, 2]);
+  });
+
+  it("Given 5, 5 is returned", function() {
+    expect(factors(5)).toEqual([5]);
+  });
+
+  it("Given 6, 2 and 3 is returned", function() {
+    expect(factors(6)).toEqual([2, 3]);
+  });
+
+  it("Given 7, 7 is returned", function() {
+    expect(factors(7)).toEqual([7]);
+  });
+
+  it("Given 8; 2, 2, and 2 is returned", function() {
+    expect(factors(8)).toEqual([2, 2, 2]);
+  });
+
+  it("Given a large number, many primes factors are returned", function() {
+    expect(factors(2*2*2*3*3*7*11*17))
+      .toEqual([2, 2, 2, 3, 3, 7, 11, 17]);
+  });
+
+  it("Given a large prime number, that number is returned", function() {
+    expect(factors(997)).toEqual([997]);
+  });
+});