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66 lines
2.4 KiB
HTML
66 lines
2.4 KiB
HTML
<p>You are given a string <code>s</code> consisting of digits. Perform the following operation repeatedly until the string has <strong>exactly</strong> two digits:</p>
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<ul>
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<li>For each pair of consecutive digits in <code>s</code>, starting from the first digit, calculate a new digit as the sum of the two digits <strong>modulo</strong> 10.</li>
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<li>Replace <code>s</code> with the sequence of newly calculated digits, <em>maintaining the order</em> in which they are computed.</li>
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</ul>
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<p>Return <code>true</code> if the final two digits in <code>s</code> are the <strong>same</strong>; otherwise, return <code>false</code>.</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">s = "3902"</span></p>
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<p><strong>Output:</strong> <span class="example-io">true</span></p>
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<p><strong>Explanation:</strong></p>
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<ul>
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<li>Initially, <code>s = "3902"</code></li>
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<li>First operation:
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<ul>
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<li><code>(s[0] + s[1]) % 10 = (3 + 9) % 10 = 2</code></li>
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<li><code>(s[1] + s[2]) % 10 = (9 + 0) % 10 = 9</code></li>
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<li><code>(s[2] + s[3]) % 10 = (0 + 2) % 10 = 2</code></li>
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<li><code>s</code> becomes <code>"292"</code></li>
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</ul>
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</li>
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<li>Second operation:
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<ul>
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<li><code>(s[0] + s[1]) % 10 = (2 + 9) % 10 = 1</code></li>
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<li><code>(s[1] + s[2]) % 10 = (9 + 2) % 10 = 1</code></li>
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<li><code>s</code> becomes <code>"11"</code></li>
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</ul>
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</li>
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<li>Since the digits in <code>"11"</code> are the same, the output is <code>true</code>.</li>
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</ul>
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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">s = "34789"</span></p>
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<p><strong>Output:</strong> <span class="example-io">false</span></p>
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<p><strong>Explanation:</strong></p>
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<ul>
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<li>Initially, <code>s = "34789"</code>.</li>
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<li>After the first operation, <code>s = "7157"</code>.</li>
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<li>After the second operation, <code>s = "862"</code>.</li>
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<li>After the third operation, <code>s = "48"</code>.</li>
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<li>Since <code>'4' != '8'</code>, the output is <code>false</code>.</li>
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</ul>
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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>3 <= s.length <= 100</code></li>
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<li><code>s</code> consists of only digits.</li>
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</ul>
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