Merge pull request #3249 from nkawaller/pow-x-n

Create: 0050-powx-n.rs

Author: Ykhan799

Diff for: rust/0050-powx-n.rs

@@ -0,0 +1,26 @@
+impl Solution {
+    pub fn my_pow(x: f64, n: i32) -> f64 {
+        fn helper(x: f64, n: i32) -> f64 {
+            match (x, n) {
+                (0.0, _) => 0.0,
+                (_, 0) => 1.0,
+                _ => {
+                    let res = helper(x * x, n / 2);
+                    if n % 2 == 0 {
+                        res
+                    } else {
+                        x * res
+                    }
+                }
+            }
+        }
+
+        let res = helper(x, n.abs());
+
+        if n >= 0 {
+            res
+        } else {
+            1.0 / res
+        }
+    }
+}