LCOF16

[underwindfall]

• https://leetcode-cn.com/problems/shu-zhi-de-zheng-shu-ci-fang-lcof/

• 思路

  • 快速密

• 刷15mins

• 刷5mins

// time O(logN)
    // space O(logN)
    public double myPow(double x, int n) {
        return n >= 0 ? quickMul(x, n) : 1.0 / quickMul(x, -n);
    }

    double quickMul(double x, int n) {
        if (n == 0) {
            return 1.0;
        }
        double y = quickMul(x, n / 2);
        return n % 2 == 0 ? y * y : y * y * x;
    }