Implement pow(x, n), which calculates x raised to the power n (i.e., xn).
Example 1:
Input: x = 2.00000, n = 10 Output: 1024.00000
Example 2:
Input: x = 2.10000, n = 3 Output: 9.26100
Example 3:
Input: x = 2.00000, n = -2 Output: 0.25000 Explanation: 2-2 = 1/22 = 1/4 = 0.25
Constraints:
-100.0 < x < 100.0-231 <= n <= 231-1n is an integer.x is not zero or n > 0.-104 <= xn <= 104class Solution {
public double myPow(double x, int n) {
if (x == 1)
return 1;
if (n < 0)
return pow(1d / x, -(long) n);
return pow(x, n);
}
private double pow(double x, long n) {
if (n == 0)
return 1;
if (n == 1)
return x;
if (n % 2 == 0)
return pow(x * x, n / 2);
return x * pow(x, n - 1);
}
}