77. 组合

function combine(n: number, k: number): number[][] {
    let result = [];
    let path = [];

    const backTracking = (n: number, k: number, startIndex: number) => {
        if (path.length === k) {
            result.push([...path]);
            return;
        };
        for (let i = startIndex; i <= n - (k - path.length) + 1; i++) {
            path.push(i);
            backTracking(n, k, i + 1);
            path.pop();
        }
    };

    backTracking(n, k, 1);
    return result;
};