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export default function diffWaysToCompute(expression: string): number[] {    if (/^\d+$/g.test(expression)) {        return [Number(expression)];    }    const regexp = /(?<operator>[\+\-\*])|(?<digit>\d+)/g;    const groups = Array.from(expression.matchAll(regexp)).map(        (a) => a.groups,    ) as unknown as (        | {            digit: string;            operator?: undefined;        }        | {            digit?: undefined;            operator: string;        }    )[];    const ans: number[] = diffWaysCalc(groups);    return ans;}function diffWaysCalc(    groups: (        | {            digit: number | string;            operator?: undefined;        }        | {            digit?: undefined;            operator: string;        }    )[],): number[] {    if (groups.length === 1) {        return [Number(groups[0].digit)];    }    if (groups.length === 3) {        return [calc_three(groups)];    }
    const ans: number[] = [];    for (let i = 1; i < groups.length; i += 2) {        const operator = groups[i];        const left = diffWaysCalc(groups.slice(0, i));        const right = diffWaysCalc(groups.slice(i + 1));
        left.map((a) =>            right.map((b) => calc_three([{ digit: a }, operator, { digit: b }]))        ).forEach((a) => ans.push(...a));    }    return ans;}function calc_three(    groups: (        | {            digit: number | string;            operator?: undefined;        }        | {            digit?: undefined;            operator: string;        }    )[],): number {    if (groups.length === 3) {        const [a, b, c] = groups;        if (b.operator === "+") {            return Number(a.digit) + Number(c.digit);        }        if (b.operator === "-") {            return Number(a.digit) - Number(c.digit);        }        if (b.operator === "*") {            return Number(a.digit) * Number(c.digit);        }    }    throw Error("groups length not three or operator not +,-,*");}