Binary Search：leetcode 50 Pow(x,n)
The article explains how to implement binary search method to find Pow(x,n) with the best approach.
Realize the functionality of Pow(x, n) ，i.e, compute \(x^n\).
Example 1：
1Input：x = 2.00000, n = 10
2Output：1024.00000
Example 2：
1Input：x = 2.00000, n = -2
2Output：0.25000
3Explain：2^{-2} = (1/2)^2 = 1/4 = 0.25
Solution:
1package main
2
3import (
4 "fmt"
5)
6
7func myPow(x float64, n int) float64 {
8 if n >= 0 {
9 return quickMul(x, n)
10 }
11 return 1.0 / quickMul(x, -n)
12}
13
14func quickMul(x float64, n int) float64 {
15 if n == 0 {
16 return 1
17 }
18 y := quickMul(x, n/2)
19 if n%2 == 0 {
20 return y * y
21 }
22 return y * y * x
23}
24
25func main() {
26 fmt.Println(quickMul(1.5, 2)) // print 2.25
27}