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export default function generate(numRows: number): number[][] {    const ret = [];
    for (let i = 0; i < numRows; i++) {        const row = new Array(i + 1).fill(1);        for (let j = 1; j < row.length - 1; j++) {            row[j] = ret[i - 1][j - 1] + ret[i - 1][j];        }        ret.push(row);    }    return ret;}