LeetCode [50] Pow(x, n)

 50. Pow(x, n)

Medium

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 <= 231-1
• -104 <= xn <= 104

1 2 3 4 5 6 7 8 9 10 11

class Solution { public: double myPow(double x, int n){ if(n==0) return 1; int absn = abs(n); double res = myPow(x, absn/2); res *= res; if(absn%2==1) res*=x; return n<0?1/res:res; } };