Initial QSfera import

Server/vendor/github.com/trustelem/zxcvbn/internal/mathutils/mathutils.go

@@ -0,0 +1,51 @@
+package mathutils
+
+func Min(a, b int) int {
+	if a < b {
+		return a
+	}
+	return b
+}
+
+func Max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+func Abs(a int) int {
+	if a < 0 {
+		return -a
+	}
+	return a
+}
+
+func NCk(n int, k int) float64 {
+	// http://blog.plover.com/math/choose.html
+	if k > n {
+		return 0
+	}
+	if k == 0 {
+		return 1
+	}
+	r := float64(1)
+	for d := 1; d <= k; d++ {
+		r *= float64(n)
+		r /= float64(d)
+		n--
+	}
+	return r
+}
+
+func Factorial(n int) float64 {
+	// unoptimized, called only on small n
+	if n < 2 {
+		return 1
+	}
+	f := float64(1)
+	for i := 2; i <= n; i++ {
+		f *= float64(i)
+	}
+	return f
+}