12345678910111213141516171819202122
import { multiply_Mod } from "./multiply_Mod.ts";
export function pow_bigint_mod(x: bigint, n: bigint, m: 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_mod(-x, n, m) % m)        : x === 1n        ? 1n        : x === 0n        ? 0n        : n === 0n        ? 1n        : n % 2n        ? multiply_Mod(x, pow_bigint_mod(x, n - 1n, m), m)        : pow_bigint_mod(multiply_Mod(x, x, m), n / 2n, m) % m;    return result;}