Sync LeetCode submission - Pow(x, n) (java)

thatbeautifuldream · thatbeautifuldream · commit 1442611f3531 · 2021-09-20T14:12:36.000Z
diff --git a/practice/problems/pow(x,_n)/solution.java b/practice/problems/pow(x,_n)/solution.java
@@ -0,0 +1,33 @@
+class Solution {
+    public double myPow(double x, int n) {
+        if(n>=0) {
+            return posPow(x,n);
+        } else {
+            return negPow(x,n);
+        }
+    }
+    private double posPow(double x, int n) {
+        if(n==0) {
+            return 1;
+        }
+        double y = myPow(x,n/2);
+        if(n%2==0) {
+            return y*y;
+        }
+        else {
+            return x*y*y;
+        }
+    }
+    private double negPow(double x, int n) {
+        if(n==-1) {
+            return 1/x;
+        }
+        double y = myPow(x,n/2);
+        if(n%2==0) {
+            return y*y;
+        }
+        else {
+            return (1/x)*y*y;
+        }
+    }
+}
