50. Pow(x, n) (java)

Author: bluesword12350

solution/0050.Pow(x, n)/Solution.java

@@ -0,0 +1,13 @@
+class Solution {
+    public double myPow(double x, int n) {
+        if(n < 0) return sum(1.0 / x,0 - n);
+        return sum(x,n);
+    }
+
+    public double sum(double x, int n) {
+        if(n == 0) return 1;
+        if(n == 1) return x;
+        if( n % 2 == 0) return sum(x * x, n / 2);
+        else return x * sum(x * x, n / 2);
+    }
+}