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45 lines
1.7 KiB
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45 lines
1.7 KiB
HTML
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<p>有 <code>n</code> 个网络节点，标记为 <code>1</code> 到 <code>n</code>。</p>
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<p>给你一个列表 <code>times</code>，表示信号经过 <strong>有向</strong> 边的传递时间。 <code>times[i] = (u<sub>i</sub>, v<sub>i</sub>, w<sub>i</sub>)</code>，其中 <code>u<sub>i</sub></code> 是源节点，<code>v<sub>i</sub></code> 是目标节点， <code>w<sub>i</sub></code> 是一个信号从源节点传递到目标节点的时间。</p>
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<p>现在，从某个节点 <code>K</code> 发出一个信号。需要多久才能使所有节点都收到信号？如果不能使所有节点收到信号，返回 <code>-1</code> 。</p>
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<p> </p>
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<p><strong>示例 1：</strong></p>
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<p><img alt="" src="https://assets.leetcode.com/uploads/2019/05/23/931_example_1.png" style="height: 220px; width: 200px;" /></p>
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<pre>
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<strong>输入：</strong>times = [[2,1,1],[2,3,1],[3,4,1]], n = 4, k = 2
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<strong>输出：</strong>2
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</pre>
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<p><strong>示例 2：</strong></p>
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<pre>
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<strong>输入：</strong>times = [[1,2,1]], n = 2, k = 1
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<strong>输出：</strong>1
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</pre>
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<p><strong>示例 3：</strong></p>
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<pre>
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<strong>输入：</strong>times = [[1,2,1]], n = 2, k = 2
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<strong>输出：</strong>-1
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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 <= k <= n <= 100</code></li>
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<li><code>1 <= times.length <= 6000</code></li>
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<li><code>times[i].length == 3</code></li>
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<li><code>1 <= u<sub>i</sub>, v<sub>i</sub> <= n</code></li>
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<li><code>u<sub>i</sub> != v<sub>i</sub></code></li>
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<li><code>0 <= w<sub>i</sub> <= 100</code></li>
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<li>所有 <code>(u<sub>i</sub>, v<sub>i</sub>)</code> 对都 <strong>互不相同</strong>（即，不含重复边）</li>
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</ul>
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