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42 lines
1.8 KiB
HTML
42 lines
1.8 KiB
HTML
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<p>实现一个 <code>MapSum</code> 类，支持两个方法，<code>insert</code> 和 <code>sum</code>：</p>
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<ul>
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<li><code>MapSum()</code> 初始化 <code>MapSum</code> 对象</li>
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<li><code>void insert(String key, int val)</code> 插入 <code>key-val</code> 键值对，字符串表示键 <code>key</code> ，整数表示值 <code>val</code> 。如果键 <code>key</code> 已经存在，那么原来的键值对将被替代成新的键值对。</li>
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<li><code>int sum(string prefix)</code> 返回所有以该前缀 <code>prefix</code> 开头的键 <code>key</code> 的值的总和。</li>
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</ul>
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<p> </p>
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<p><strong>示例：</strong></p>
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<pre>
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<strong>输入：</strong>
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inputs = ["MapSum", "insert", "sum", "insert", "sum"]
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inputs = [[], ["apple", 3], ["ap"], ["app", 2], ["ap"]]
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<strong>输出：</strong>
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[null, null, 3, null, 5]
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<strong>解释：</strong>
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MapSum mapSum = new MapSum();
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mapSum.insert("apple", 3);
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mapSum.sum("ap"); // return 3 (<u>ap</u>ple = 3)
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mapSum.insert("app", 2);
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mapSum.sum("ap"); // return 5 (<u>ap</u>ple + <u>ap</u>p = 3 + 2 = 5)
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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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<ul>
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<li><code>1 <= key.length, prefix.length <= 50</code></li>
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<li><code>key</code> 和 <code>prefix</code> 仅由小写英文字母组成</li>
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<li><code>1 <= val <= 1000</code></li>
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<li>最多调用 <code>50</code> 次 <code>insert</code> 和 <code>sum</code></li>
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</ul>
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<p> </p>
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<p><meta charset="UTF-8" />注意：本题与主站 677 题相同： <a href="https://leetcode-cn.com/problems/map-sum-pairs/">https://leetcode-cn.com/problems/map-sum-pairs/</a></p>
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