50. Pow(x, n) [Leetcode][C++]

class Solution { public: double myPow(double x, int n) { // Brute Force Solution Time O(N) & Auxiliary Space O(N) if(n==0) return 1; else if(n>0) return x*myPow(x,n-1); else return (1/x)*myPow(x,n+1); } }; 

class Solution { public: double myPow(double x, int n) { // Optimal Solution Time O(logN) & Auxiliary Space O(logN) if(n==0) return 1; // Using Binary Exponentiation(Time O(logN)) // x^n=x^(n/2)*x^(n/2). So, recursive function is  // called logN times where y=x^(n/2) and function returns y*y double y = myPow(x,n/2); if(n%2==0) return y*y; else if(n < 0) return 1/x*y*y; else return x*y*y; } };