50. Pow(x, n)

Implement pow(x, n).

Example 1:

Input: 2.00000, 10
Output: 1024.00000

Example 2:

Input: 2.10000, 3
Output: 9.26100

Analysis

link: https://leetcode.com/problems/powx-n/solution/

https://leetcode.com/problems/powx-n/discuss/19563/Iterative-Log(N)-solution-with-Clear-Explanation

Solution from web

public double myPow(double x, int n) {
    long N = n;
    if (N < 0) {
        x = 1 / x;
        N = -N;
    }
    double ans = 1;
    double current_product = x;
    for (long i = N; i > 0; i /= 2) {
        if ((i % 2) == 1) {
            ans = ans * current_product;
        }
        current_product = current_product * current_product;
    }
    return ans;
}