const countSubsetsOfSizeK = (n, k) => {
    if (k === 0 || k === n) return 1;

    const table = new Array(n + 1).fill(0).map(() => new Array(k + 1).fill(0));

    // all row[0] (first column) set to 1
    for (let r = 0; r <= n; r++) {
        table[r][0] = 1;
    }

    // diagonal set to 1
    for (let c = 0; c <= k; c++) {
        table[c][c] = 1;
    }

    for (let row = 2; row <= n; row++) {
        for (let col = 1; col <= Math.min(row, k); col++) {
            table[row][col] = table[row - 1][col] + table[row - 1][col - 1]
        }

    }
    return table[n][k];
}