subsets II

Author: zgpeace

code/LeetCode/src/backtracking/SubsetsII.java

@@ -0,0 +1,67 @@
+package backtracking;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+// https://leetcode.com/problems/subsets-ii/
+public class SubsetsII {
+
+  public static void main(String[] args) {
+    int[] nums = {1,2,2};
+    SubsetsII obj = new SubsetsII();
+    List<List<Integer>> resultList = obj.subsetsWithDup(nums);
+    System.out.println(Arrays.toString(resultList.toArray()));
+  }
+
+  public List<List<Integer>> subsetsWithDup(int[] nums) {
+    Arrays.sort(nums);
+    List<List<Integer>> resultList = new ArrayList<List<Integer>>();
+    // dfs
+    dfs(nums, resultList, new ArrayList<Integer>(), 0);
+
+    return resultList;
+  }
+
+  private void dfs(int[] nums, List<List<Integer>> resultList, List<Integer> list, int start) {
+    if (start <= nums.length) {
+      resultList.add(list);
+    }
+    int i = start;
+    while (i < nums.length) {
+      list.add(nums[i]);
+      dfs(nums, resultList, new ArrayList<Integer>(list), i + 1);
+
+      list.remove(list.size() - 1);
+      i++;
+      while (i < nums.length && nums[i] == nums[i - 1]) {
+        i++;
+      }
+    }
+
+  }
+
+  // still have some duplicate data
+  //private void dfs1(int[] nums, List<List<Integer>> resultList, List<Integer> list, int start) {
+  //  // exit
+  //  if (start == nums.length) {
+  //    resultList.add(new ArrayList<>(list));
+  //    return;
+  //  }
+  //
+  //  for (int i = start; i < nums.length; i++) {
+  //    // duplicate case
+  //    if (i > start && nums[i] == nums[i - 1]) {
+  //      continue;
+  //    }
+  //
+  //    // pick up
+  //    list.add(nums[i]);
+  //    dfs(nums, resultList, list, i + 1);
+  //
+  //    // not pick up
+  //    list.remove(list.size() - 1);
+  //    dfs(nums, resultList, list, i + 1);
+  //  }
+  //}
+}