Merge pull request #178

kde_intellij

Author: rajeshsantha

src/com/concept/scala/leetcode_30days_challenge_July2020/X_Pow_of_N.scala

@@ -0,0 +1,45 @@
+package com.concept.scala.leetcode_30days_challenge_July2020
+
+/** *
+ *
+ * day 16
+ *
+ * @todo Implement pow(x, n), which calculates x raised to the power n (x pow n).
+ * @example Example 1:
+ *
+ * Input: 2.00000, 10
+ * Output: 1024.00000
+ * Example 2:
+ *
+ * Input: 2.10000, 3
+ * Output: 9.26100
+ * Example 3:
+ *
+ * Input: 2.00000, -2
+ * Output: 0.25000
+ * Explanation: 2-2 = 1/22 = 1/4 = 0.25
+ * @note -100.0 < x < 100.0
+ * n is a 32-bit signed integer, within the range [−2 pow 31, 2 pow 31 − 1]
+ */
+object X_Pow_of_N {
+ def main(args: Array[String]): Unit = {
+ println(myPow_recursive(2.00000, -2))
+ }
+
+ def myPow(x: Double, n: Int): Double = scala.math.pow(x, n)
+
+
+ def myPow_recursive(x: Double, n: Int): Double = {
+
+ def helper(x: Double, n: Int): Double = {
+ (x, n) match {
+ case (_, 0) => 1
+ case (1, _) => 1
+ case (base, power) if power % 2 == 0 => helper(base * base, power / 2)
+ case (base, power) => base * helper(base * base, power / 2)
+ }
+ }
+
+ if (n < 0) if (n == Int.MinValue) 1 / myPow(x, -(n + 1)) / x else 1 / myPow(x, -n) else helper(x, n)
+ }
+}