热题 HOT 100

22.括号生成(dfs)easy
21.合并两个有序列表(模拟)easy

23. 合并K个升序链表(优先队列)中等

46. 全排列 dfs

/**
 * @param {number[]} nums
 * @return {number[][]}
 */
var permute = function(nums) {
    const dfs = (path,k,used) => {
        if(path.length === nums.length) {
            res.push(Array.from(path))
            return;
        }
        for(let i = 0; i < k ; i ++) {
            if(used[i]) continue;
            used[i] = true;
            path.push(nums[i])
            dfs(path,nums.length,used)
            used[i] = false;
            path.pop()
        }
    }
    const res = [] , path = []
    dfs(path,nums.length,[]);
    return res;
};