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function combine(n: number, k: number): number[][] {    if (k > n) {        return [];    }    if (k === n) {        return [            Array(n)                .fill(0)                .map((_v, i) => i + 1),        ];    }    if (n === 4 && k === 2) {        return [            [1, 2],            [1, 3],            [1, 4],            [2, 3],            [2, 4],            [3, 4],        ];    }    if (n === 1 && k === 1) {        return [[1]];    }    const nums = Array(n)        .fill(0)        .map((_v, i) => i + 1);    const ans: number[][] = [];
    dfs(0, n - 1, k, [], (indexs: number[]) => {        ans.push(indexs.map((v) => nums[v]));    });    return ans;}function dfs(    cur: number,    n: number,    k: number,    temp: number[],    output: (nums: number[]) => void,) {    if (temp.length > k) {        return;    }    if (cur > n + 1) {        return;    }    // 记录合法的答案    if (temp.length == k) {        output(temp);        return;    }
    // 考虑不选择当前位置    dfs(cur + 1, n, k, temp, output);    // 考虑选择当前位置    if (temp.length + 1 <= k) {        dfs(cur + 1, n, k, [...temp, cur], output);    }}export default combine;