Pow(x, n)

Leetcode Problem 50: Pow(x, n)

Problem Summary

Implement pow(x, n), computing x raised to the power n. Handle both positive and negative exponents, and both positive and negative bases.

Constraints:

• x is a floating-point number in the open range (-100.0, 100.0).
• n is a 32-bit signed integer in the range [-(2^31), 2^31 − 1].
• Either x is non-zero, or n is positive (0^0 and 0^(negative) will not occur).

Techniques

• Math
• Recursion

Solution

function myPow(x: number, n: number): number {
    if (n === 0) return 1;

    if (n < 0) {
        return 1 / myPow(x, -n);
    }

    const half = myPow(x, Math.floor(n / 2));

    if (n % 2 === 0) {
        return half * half;
    } else {
        return half * half * x;
    }
}

console.log(myPow(2, 10));
console.log(myPow(2, -2));
console.log(myPow(2.1, 3));