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45 lines
1.1 KiB
HTML
45 lines
1.1 KiB
HTML
<p>给定一个对象或数组，判断它是否为空。</p>
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<ul>
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<li>一个空对象不包含任何键值对。</li>
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<li>一个空数组不包含任何元素。</li>
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</ul>
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<p>你可以假设对象或数组是通过 <code>JSON.parse</code> 解析得到的。</p>
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<p> </p>
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<p><strong class="example">示例 1：</strong></p>
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<pre>
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<b>输入：</b>obj = {"x": 5, "y": 42}
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<b>输出：</b>false
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<b>解释：</b>The object has 2 key-value pairs so it is not empty.
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</pre>
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<p><strong class="example">示例 2：</strong></p>
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<pre>
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<b>输入：</b>obj = {}
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<b>输出：</b>true
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<b>解释：</b>The object doesn't have any key-value pairs so it is empty.
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</pre>
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<p><strong class="example">示例 3：</strong></p>
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<pre>
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<b>输入：</b>obj = [null, false, 0]
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<b>输出：</b>false
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<b>解释：</b>The array has 3 elements so it is not empty.
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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>2 <= JSON.stringify(obj).length <= 10<sup>5</sup></code></li>
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</ul>
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<p> </p>
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<strong>你可以在 O(1) 时间复杂度内解决这个问题吗？</strong> |