90. Subsets II (java)

Author: bluesword12350

solution/0090.Subsets II/Solution.java

@@ -0,0 +1,19 @@
+class Solution {
+    public List<List<Integer>> subsetsWithDup(int[] nums) {
+        List<List<Integer>> res = new ArrayList<>();
+        if(nums==null||nums.length==0) return res;
+        Arrays.sort(nums);
+        backTrack(res, nums, 0, new ArrayList<>());
+        return res;
+    }
+    private void backTrack(List<List<Integer>> res, int[] nums, int index, List<Integer> ls){
+        res.add(new ArrayList<>(ls));
+        if(index>=nums.length) return;
+        for(int i=index;i<nums.length;i++){
+            ls.add(nums[i]);
+            backTrack(res, nums, i+1, ls);
+            ls.remove(ls.size()-1);
+            while(i<nums.length-1 && nums[i+1]==nums[i]) i++;
+        }
+    }
+}