20240802 Finished

src/problem/mod.rs

@@ -191,4 +191,5 @@ mod p137_single_number_ii;
 mod p201_bitwise_and_of_numbers_range;
 mod p66_plus_one;
 mod p172_factorial_trailing_zeroes;
-mod p69_sqrtx;
+mod p69_sqrtx;
+mod p50_powx_n;

src/problem/p50_powx_n.rs

@@ -0,0 +1,41 @@
+/**
+ * [50] Pow(x, n)
+ */
+pub struct Solution {}
+
+
+// submission codes start here
+
+impl Solution {
+    pub fn my_pow(x: f64, n: i32) -> f64 {
+        if n < 0 {
+            1f64 / Self::quick_pow(x, -n)
+        } else {
+            Self::quick_pow(x, n)
+        }
+    }
+    
+    fn quick_pow(x: f64, n: i32) -> f64 {
+        if n == 0 {
+            1f64
+        } else { 
+            let y = Self::quick_pow(x, n / 2);
+            if n % 2 == 0 {
+                y * y
+            } else { 
+                y * y * x
+            }
+        }
+    }
+}
+
+// submission codes end
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_50() {
+    }
+}