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58 lines
2.6 KiB
HTML
58 lines
2.6 KiB
HTML
<p>You are given a phone number as a string <code>number</code>. <code>number</code> consists of digits, spaces <code>' '</code>, and/or dashes <code>'-'</code>.</p>
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<p>You would like to reformat the phone number in a certain manner. Firstly, <strong>remove</strong> all spaces and dashes. Then, <strong>group</strong> the digits from left to right into blocks of length 3 <strong>until</strong> there are 4 or fewer digits. The final digits are then grouped as follows:</p>
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<ul>
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<li>2 digits: A single block of length 2.</li>
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<li>3 digits: A single block of length 3.</li>
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<li>4 digits: Two blocks of length 2 each.</li>
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</ul>
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<p>The blocks are then joined by dashes. Notice that the reformatting process should <strong>never</strong> produce any blocks of length 1 and produce <strong>at most</strong> two blocks of length 2.</p>
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<p>Return <em>the phone number after formatting.</em></p>
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<p> </p>
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<p><strong>Example 1:</strong></p>
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<pre>
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<strong>Input:</strong> number = "1-23-45 6"
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<strong>Output:</strong> "123-456"
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<strong>Explanation:</strong> The digits are "123456".
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Step 1: There are more than 4 digits, so group the next 3 digits. The 1st block is "123".
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Step 2: There are 3 digits remaining, so put them in a single block of length 3. The 2nd block is "456".
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Joining the blocks gives "123-456".
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</pre>
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<p><strong>Example 2:</strong></p>
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<pre>
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<strong>Input:</strong> number = "123 4-567"
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<strong>Output:</strong> "123-45-67"
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<strong>Explanation: </strong>The digits are "1234567".
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Step 1: There are more than 4 digits, so group the next 3 digits. The 1st block is "123".
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Step 2: There are 4 digits left, so split them into two blocks of length 2. The blocks are "45" and "67".
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Joining the blocks gives "123-45-67".
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</pre>
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<p><strong>Example 3:</strong></p>
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<pre>
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<strong>Input:</strong> number = "123 4-5678"
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<strong>Output:</strong> "123-456-78"
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<strong>Explanation:</strong> The digits are "12345678".
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Step 1: The 1st block is "123".
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Step 2: The 2nd block is "456".
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Step 3: There are 2 digits left, so put them in a single block of length 2. The 3rd block is "78".
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Joining the blocks gives "123-456-78".
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</pre>
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<p> </p>
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<p><strong>Constraints:</strong></p>
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<ul>
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<li><code>2 <= number.length <= 100</code></li>
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<li><code>number</code> consists of digits and the characters <code>'-'</code> and <code>' '</code>.</li>
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<li>There are at least <strong>two</strong> digits in <code>number</code>.</li>
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</ul>
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