981:基于时间的键值存储
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src/main/java/leetcode/editor/cn/TimeBasedKeyValueStore.java
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113
src/main/java/leetcode/editor/cn/TimeBasedKeyValueStore.java
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//创建一个基于时间的键值存储类 TimeMap，它支持下面两个操作：
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//
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// 1. set(string key, string value, int timestamp)
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//
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//
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// 存储键 key、值 value，以及给定的时间戳 timestamp。
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//
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//
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// 2. get(string key, int timestamp)
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//
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//
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// 返回先前调用 set(key, value, timestamp_prev) 所存储的值，其中 timestamp_prev <= timestamp。
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//
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// 如果有多个这样的值，则返回对应最大的 timestamp_prev 的那个值。
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// 如果没有值，则返回空字符串（""）。
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//
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//
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//
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//
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// 示例 1：
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//
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// 输入：inputs = ["TimeMap","set","get","get","set","get","get"], inputs = [[],["f
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//oo","bar",1],["foo",1],["foo",3],["foo","bar2",4],["foo",4],["foo",5]]
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//输出：[null,null,"bar","bar",null,"bar2","bar2"]
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//解释：
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//TimeMap kv;
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//kv.set("foo", "bar", 1); // 存储键 "foo" 和值 "bar" 以及时间戳 timestamp = 1
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//kv.get("foo", 1); // 输出 "bar"
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//kv.get("foo", 3); // 输出 "bar" 因为在时间戳 3 和时间戳 2 处没有对应 "foo" 的值，所以唯一的值位于时间戳 1 处（即
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// "bar"）
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//kv.set("foo", "bar2", 4);
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//kv.get("foo", 4); // 输出 "bar2"
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//kv.get("foo", 5); // 输出 "bar2"
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//
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//
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//
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// 示例 2：
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//
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// 输入：inputs = ["TimeMap","set","set","get","get","get","get","get"], inputs = [
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//[],["love","high",10],["love","low",20],["love",5],["love",10],["love",15],["lov
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//e",20],["love",25]]
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//输出：[null,null,null,"","high","high","low","low"]
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//
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//
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//
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//
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// 提示：
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//
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//
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// 所有的键/值字符串都是小写的。
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// 所有的键/值字符串长度都在 [1, 100] 范围内。
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// 所有 TimeMap.set 操作中的时间戳 timestamps 都是严格递增的。
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// 1 <= timestamp <= 10^7
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// TimeMap.set 和 TimeMap.get 函数在每个测试用例中将（组合）调用总计 120000 次。
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//
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// Related Topics 设计 哈希表 字符串 二分查找
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// 👍 120 👎 0
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package leetcode.editor.cn;
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import java.util.*;
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//981:基于时间的键值存储
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class TimeBasedKeyValueStore {
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public static void main(String[] args) {
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//测试代码
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// Solution solution = new TimeBasedKeyValueStore().new Solution();
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}
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//力扣代码
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//leetcode submit region begin(Prohibit modification and deletion)
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class TimeMap {
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class Node {
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String k, v;
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int t;
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Node (String _k, String _v, int _t) {
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k = _k; v = _v; t = _t;
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}
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}
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Map<String, List<Node>> map = new HashMap<>();
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public void set(String k, String v, int t) {
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List<Node> list = map.getOrDefault(k, new ArrayList<>());
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list.add(new Node(k, v, t));
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map.put(k, list);
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}
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public String get(String k, int t) {
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List<Node> list = map.getOrDefault(k, new ArrayList<>());
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if (list.isEmpty()) return "";
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int n = list.size();
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int l = 0, r = n - 1;
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while (l < r) {
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int mid = l + r + 1 >> 1;
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if (list.get(mid).t <= t) {
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l = mid;
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} else {
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r = mid - 1;
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}
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}
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return list.get(r).t <= t ? list.get(r).v : "";
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}
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}
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/**
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* Your TimeMap object will be instantiated and called as such:
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* TimeMap obj = new TimeMap();
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* obj.set(key,value,timestamp);
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* String param_2 = obj.get(key,timestamp);
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*/
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//leetcode submit region end(Prohibit modification and deletion)
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}
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51
src/main/java/leetcode/editor/cn/TimeBasedKeyValueStore.md
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src/main/java/leetcode/editor/cn/TimeBasedKeyValueStore.md
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<p>创建一个基于时间的键值存储类 <code>TimeMap</code>，它支持下面两个操作：</p>
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<p>1. <code>set(string key, string value, int timestamp)</code></p>
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<ul>
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<li>存储键 <code>key</code>、值 <code>value</code>，以及给定的时间戳 <code>timestamp</code>。</li>
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</ul>
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<p>2. <code>get(string key, int timestamp)</code></p>
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<ul>
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<li>返回先前调用 <code>set(key, value, timestamp_prev)</code> 所存储的值，其中 <code>timestamp_prev <= timestamp</code>。</li>
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<li>如果有多个这样的值，则返回对应最大的 <code>timestamp_prev</code> 的那个值。</li>
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<li>如果没有值，则返回空字符串（<code>""</code>）。</li>
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</ul>
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<p> </p>
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<p><strong>示例 1：</strong></p>
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<pre><strong>输入：</strong>inputs = ["TimeMap","set","get","get","set","get","get"], inputs = [[],["foo","bar",1],["foo",1],["foo",3],["foo","bar2",4],["foo",4],["foo",5]]
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<strong>输出：</strong>[null,null,"bar","bar",null,"bar2","bar2"]
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<strong>解释：</strong>
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TimeMap kv;
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kv.set("foo", "bar", 1); // 存储键 "foo" 和值 "bar" 以及时间戳 timestamp = 1
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kv.get("foo", 1); // 输出 "bar"
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kv.get("foo", 3); // 输出 "bar" 因为在时间戳 3 和时间戳 2 处没有对应 "foo" 的值，所以唯一的值位于时间戳 1 处（即 "bar"）
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kv.set("foo", "bar2", 4);
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kv.get("foo", 4); // 输出 "bar2"
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kv.get("foo", 5); // 输出 "bar2"
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</pre>
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<p><strong>示例 2：</strong></p>
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<pre><strong>输入：</strong>inputs = ["TimeMap","set","set","get","get","get","get","get"], inputs = [[],["love","high",10],["love","low",20],["love",5],["love",10],["love",15],["love",20],["love",25]]
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<strong>输出：</strong>[null,null,null,"","high","high","low","low"]
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</pre>
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<p> </p>
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<p><strong>提示：</strong></p>
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<ol>
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<li>所有的键/值字符串都是小写的。</li>
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<li>所有的键/值字符串长度都在 <code>[1, 100]</code> 范围内。</li>
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<li>所有 <code>TimeMap.set</code> 操作中的时间戳 <code>timestamps</code> 都是严格递增的。</li>
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<li><code>1 <= timestamp <= 10^7</code></li>
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<li><code>TimeMap.set</code> 和 <code>TimeMap.get</code> 函数在每个测试用例中将（组合）调用总计 <code>120000</code> 次。</li>
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</ol>
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<div><div>Related Topics</div><div><li>设计</li><li>哈希表</li><li>字符串</li><li>二分查找</li></div></div>\n<div><li>👍 120</li><li>👎 0</li></div>
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