1234567891011121314151617181920
export function pow_bigint(x: bigint, n: bigint): bigint {    if (n < 0) {        throw Error("result not bigint:" + x + "," + n);    }    const result = n === 1n        ? x        : x < 0        ? (n % 2n === 0n ? 1n : -1n) * pow_bigint(-x, n)        : x === 1n        ? 1n        : x === 0n        ? 0n        : n === 0n        ? 1n        : n % 2n        ? x * pow_bigint(x, n - 1n)        : pow_bigint(x * x, n / 2n);    return result;}