回溯法 | 78.子集
class Solution {
List<List<Integer>> res = new ArrayList<>();
public List<List<Integer>> subsets(int[] nums) {
dfs(nums,0,new ArrayList<>());
res.add(new ArrayList<>());
return res;
}
public void dfs(int[] nums, int idx, List<Integer> list){
if(idx>=nums.length){
return;
}
for(int i=idx;i<nums.length;i++){
list.add(nums[i]);
res.add(new ArrayList<>(list));
dfs(nums,i+1,list);
list.remove(list.size()-1);
}
}
} 