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109 lines
3.1 KiB
HTML
109 lines
3.1 KiB
HTML
<p>Seven different symbols represent Roman numerals with the following values:</p>
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<table>
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<thead>
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<tr>
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<th>Symbol</th>
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<th>Value</th>
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</tr>
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</thead>
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<tbody>
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<tr>
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<td>I</td>
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<td>1</td>
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</tr>
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<tr>
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<td>V</td>
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<td>5</td>
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</tr>
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<tr>
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<td>X</td>
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<td>10</td>
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</tr>
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<tr>
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<td>L</td>
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<td>50</td>
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</tr>
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<tr>
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<td>C</td>
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<td>100</td>
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</tr>
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<tr>
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<td>D</td>
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<td>500</td>
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</tr>
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<tr>
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<td>M</td>
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<td>1000</td>
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</tr>
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</tbody>
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</table>
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<p>Roman numerals are formed by appending the conversions of decimal place values from highest to lowest. Converting a decimal place value into a Roman numeral has the following rules:</p>
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<ul>
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<li>If the value does not start with 4 or 9, select the symbol of the maximal value that can be subtracted from the input, append that symbol to the result, subtract its value, and convert the remainder to a Roman numeral.</li>
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<li>If the value starts with 4 or 9 use the <strong>subtractive form</strong> representing one symbol subtracted from the following symbol, for example, 4 is 1 (<code>I</code>) less than 5 (<code>V</code>): <code>IV</code> and 9 is 1 (<code>I</code>) less than 10 (<code>X</code>): <code>IX</code>. Only the following subtractive forms are used: 4 (<code>IV</code>), 9 (<code>IX</code>), 40 (<code>XL</code>), 90 (<code>XC</code>), 400 (<code>CD</code>) and 900 (<code>CM</code>).</li>
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<li>Only powers of 10 (<code>I</code>, <code>X</code>, <code>C</code>, <code>M</code>) can be appended consecutively at most 3 times to represent multiples of 10. You cannot append 5 (<code>V</code>), 50 (<code>L</code>), or 500 (<code>D</code>) multiple times. If you need to append a symbol 4 times use the <strong>subtractive form</strong>.</li>
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</ul>
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<p>Given an integer, convert it to a Roman numeral.</p>
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<p> </p>
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<p><strong class="example">Example 1:</strong></p>
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<div class="example-block">
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<p><strong>Input:</strong> <span class="example-io">num = 3749</span></p>
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<p><strong>Output:</strong> <span class="example-io">"MMMDCCXLIX"</span></p>
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<p><strong>Explanation:</strong></p>
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<pre>
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3000 = MMM as 1000 (M) + 1000 (M) + 1000 (M)
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700 = DCC as 500 (D) + 100 (C) + 100 (C)
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40 = XL as 10 (X) less of 50 (L)
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9 = IX as 1 (I) less of 10 (X)
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Note: 49 is not 1 (I) less of 50 (L) because the conversion is based on decimal places
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</pre>
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</div>
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<p><strong class="example">Example 2:</strong></p>
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<div class="example-block">
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<p><strong>Input:</strong> <span class="example-io">num = 58</span></p>
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<p><strong>Output:</strong> <span class="example-io">"LVIII"</span></p>
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<p><strong>Explanation:</strong></p>
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<pre>
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50 = L
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8 = VIII
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</pre>
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</div>
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<p><strong class="example">Example 3:</strong></p>
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<div class="example-block">
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<p><strong>Input:</strong> <span class="example-io">num = 1994</span></p>
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<p><strong>Output:</strong> <span class="example-io">"MCMXCIV"</span></p>
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<p><strong>Explanation:</strong></p>
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<pre>
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1000 = M
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900 = CM
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90 = XC
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4 = IV
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</pre>
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</div>
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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>1 <= num <= 3999</code></li>
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</ul>
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