tasks a-s

Task/Nth-root/Go/nth-root.go

@@ -0,0 +1,19 @@
+func root(a float64, n int) float64 {
+    n1 := n - 1
+    n1f, rn := float64(n1), 1/float64(n)
+    x, x0 := 1., 0.
+    for {
+        potx, t2 := 1/x, a
+        for b := n1; b > 0; b >>= 1 {
+            if b&1 == 1 {
+                t2 *= potx
+            }
+            potx *= potx
+        }
+        x0, x = x, rn*(n1f*x+t2)
+        if math.Abs(x-x0)*1e15 < x {
+            break
+        }
+    }
+    return x
+}