Solution.js

/**
 * @param {number[]} nums
 * @return {number[][]}
 */
var subsetsWithDup = function (nums) {
    nums.sort((a, b) => a - b);
    const n = nums.length;
    const t = [];
    const ans = [];
    const dfs = i => {
        if (i >= n) {
            ans.push([...t]);
            return;
        }
        t.push(nums[i]);
        dfs(i + 1);
        t.pop();
        while (i + 1 < n && nums[i] === nums[i + 1]) {
            i++;
        }
        dfs(i + 1);
    };
    dfs(0);
    return ans;
};