再次完成380

Author: diguage

docs/0380-insert-delete-getrandom-o1.adoc

@@ -41,11 +41,21 @@ randomSet.insert(2);
 randomSet.getRandom();
 ----
 
-
+== 思路分析
 
 [[src-0380]]
 [{java_src_attr}]
 ----
 include::{sourcedir}/_0380_InsertDeleteGetRandomO1.java[]
 ----
 
+[{java_src_attr}]
+----
+include::{sourcedir}/_0380_InsertDeleteGetRandomO1_2.java[]
+----
+
+== 参考资料
+
+. https://leetcode.cn/problems/insert-delete-getrandom-o1/solutions/1411578/o1-shi-jian-cha-ru-shan-chu-he-huo-qu-su-rlz2/[380. O(1) 时间插入、删除和获取随机元素 - 官方题解^]
+. https://leetcode.cn/problems/insert-delete-getrandom-o1/solutions/1416888/by-ac_oier-tpex/[380. O(1) 时间插入、删除和获取随机元素 - 【宫水三叶】数据结构运用题^]
+

logbook/202406.adoc

@@ -234,11 +234,15 @@
 |{doc_base_url}/1094-car-pooling.adoc[题解]
 |差分数组
 
-
 |1109
 |{leetcode_base_url}/corporate-flight-bookings/[Corporate Flight Bookings]
 |{doc_base_url}/1109-corporate-flight-bookings.adoc[题解]
 |差分数组
 
+|380
+|{leetcode_base_url}/insert-delete-getrandom-o1/[Insert Delete GetRandom O(1)]
+|{doc_base_url}/0380-insert-delete-getrandom-o1.adoc[题解]
+|数据结构应用
+
 
 |===

src/main/java/com/diguage/algorithm/leetcode/_0380_InsertDeleteGetRandomO1_2.java

@@ -0,0 +1,92 @@
+package com.diguage.algorithm.leetcode;
+
+import java.util.*;
+
+/**
+ * = 380. Insert Delete GetRandom O(1)
+ *
+ * https://leetcode.com/problems/insert-delete-getrandom-o1/[Insert Delete GetRandom O(1) - LeetCode]
+ *
+ * Design a data structure that supports all following operations in average *O(1)* time.
+ *
+ * . `insert(val)`: Inserts an item val to the set if not already present.
+ * . `remove(val)`: Removes an item val from the set if present.
+ * . `getRandom`: Returns a random element from current set of elements. Each element must have the *same probability* of being returned.
+ *
+ * .Example:
+ * [source]
+ * ----
+ * // Init an empty set.
+ * RandomizedSet randomSet = new RandomizedSet();
+ *
+ * // Inserts 1 to the set. Returns true as 1 was inserted successfully.
+ * randomSet.insert(1);
+ *
+ * // Returns false as 2 does not exist in the set.
+ * randomSet.remove(2);
+ *
+ * // Inserts 2 to the set, returns true. Set now contains [1,2].
+ * randomSet.insert(2);
+ *
+ * // getRandom should return either 1 or 2 randomly.
+ * randomSet.getRandom();
+ *
+ * // Removes 1 from the set, returns true. Set now contains [2].
+ * randomSet.remove(1);
+ *
+ * // 2 was already in the set, so return false.
+ * randomSet.insert(2);
+ *
+ * // Since 2 is the only number in the set, getRandom always return 2.
+ * randomSet.getRandom();
+ * ----
+ *
+ * @author D瓜哥 · https://www.diguage.com
+ * @since 2024-07-05 16:44:29
+ */
+public class _0380_InsertDeleteGetRandomO1_2 {
+  /**
+   * 自己实现
+   */
+  class RandomizedSet {
+    private List<Integer> nums;
+    private Map<Integer, Integer> idex;
+    private Random random;
+
+    public RandomizedSet() {
+      nums = new ArrayList<>();
+      random = new Random();
+      idex = new HashMap<>();
+    }
+
+    public boolean insert(int val) {
+      if (idex.containsKey(val)) {
+        return false;
+      } else {
+        nums.add(val);
+        idex.put(val, nums.size() - 1);
+        return true;
+      }
+    }
+
+    public boolean remove(int val) {
+      if (!idex.containsKey(val)) {
+        return false;
+      } else {
+        int i1 = idex.get(val);
+        if (i1 != idex.size() - 1) {
+          Integer value = nums.get(nums.size() - 1);
+          nums.set(i1, value);
+          idex.put(value, i1);
+        }
+        idex.remove(val);
+        nums.remove(nums.size() - 1);
+        return true;
+      }
+    }
+
+    public int getRandom() {
+      return nums.get(random.nextInt(nums.size()));
+    }
+  }
+}