五刷90

Author: diguage

docs/0090-subsets-ii.adoc

@@ -92,6 +92,15 @@ include::{sourcedir}/_0090_SubsetsII_31.java[tag=answer]
 include::{sourcedir}/_0090_SubsetsIi_4.java[tag=answer]
 ----
 --
+
+四刷::
++
+--
+[{java_src_attr}]
+----
+include::{sourcedir}/_0090_SubsetsIi_5.java[tag=answer]
+----
+--
 ====
 
 == 参考资料

logbook/202503.adoc

@@ -73,7 +73,7 @@ endif::[]
 |{counter:codes2503e}
 |{leetcode_base_url}/subsets-ii/[90. 子集 II]
 |{doc_base_url}/0090-subsets-ii.adoc[题解]
-|⭕️ ✅
+|⭕️ ✅ ✅
 
 |{counter:codes2503e}
 |{leetcode_base_url}/house-robber-iv/[2560. 打家劫舍 IV^]
@@ -2650,6 +2650,11 @@ endif::[]
 |{doc_base_url}/0322-coin-change.adoc[题解]
 |✅ 动态规划。无限背包问题。
 
+|{counter:codes2503}
+|{leetcode_base_url}/subsets-ii/[90. 子集 II]
+|{doc_base_url}/0090-subsets-ii.adoc[题解]
+|✅ 子集模式。需要注意重复元素的处理。如果元素中有重复元素，那么就需要先对元素排序，遇到重复元素时，就不能对虽有已有元素都添加新元素了。只需要针对上一次新添加的子集添加新元素即可，依次执行，直到有不重复元素则再次恢复成从全部子集添加元素。
+
 |===
 
 

src/main/java/com/diguage/algo/leetcode/_0090_SubsetsIi_5.java

@@ -0,0 +1,41 @@
+package com.diguage.algo.leetcode;
+
+import jnr.ffi.annotations.In;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+public class _0090_SubsetsIi_5 {
+  // tag::answer[]
+
+  /**
+   * @author D瓜哥 · https://www.diguage.com
+   * @since 2025-12-18 21:30:25
+   */
+  public List<List<Integer>> subsetsWithDup(int[] nums) {
+    Arrays.sort(nums);
+    List<List<Integer>> result = new ArrayList<>(1 << nums.length);
+    result.add(List.of());
+    result.add(List.of(nums[0]));
+    int size = result.size();
+    int addSize = 1;
+    for (int i = 1; i < nums.length; i++) {
+      int num = nums[i];
+      size = result.size();
+      int index = 0;
+      if (nums[i] == nums[i - 1]) {
+        index = size - addSize;
+      }
+      addSize = 0;
+      for (int j = index; j < size; j++) {
+        List<Integer> next = new ArrayList<>(result.get(j));
+        next.add(num);
+        result.add(next);
+        addSize++;
+      }
+    }
+    return result;
+  }
+  // end::answer[]
+}