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73 lines
2.6 KiB
HTML
73 lines
2.6 KiB
HTML
<p>You are given two integers <code>num1</code> and <code>num2</code> representing an <strong>inclusive</strong> range <code>[num1, num2]</code>.</p>
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<p>The <strong>waviness</strong> of a number is defined as the total count of its <strong>peaks</strong> and <strong>valleys</strong>:</p>
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<ul>
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<li>A digit is a <strong>peak</strong> if it is <strong>strictly greater</strong> than both of its immediate neighbors.</li>
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<li>A digit is a <strong>valley</strong> if it is <strong>strictly less</strong> than both of its immediate neighbors.</li>
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<li>The first and last digits of a number <strong>cannot</strong> be peaks or valleys.</li>
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<li>Any number with fewer than 3 digits has a waviness of 0.</li>
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</ul>
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Return the total sum of waviness for all numbers in the range <code>[num1, num2]</code>.
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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">num1 = 120, num2 = 130</span></p>
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<p><strong>Output:</strong> <span class="example-io">3</span></p>
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<p><strong>Explanation:</strong></p>
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<p>In the range <code>[120, 130]</code>:</p>
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<ul>
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<li><code>120</code>: middle digit 2 is a peak, waviness = 1.</li>
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<li><code>121</code>: middle digit 2 is a peak, waviness = 1.</li>
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<li><code>130</code>: middle digit 3 is a peak, waviness = 1.</li>
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<li>All other numbers in the range have a waviness of 0.</li>
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</ul>
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<p>Thus, total waviness is <code>1 + 1 + 1 = 3</code>.</p>
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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">num1 = 198, num2 = 202</span></p>
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<p><strong>Output:</strong> <span class="example-io">3</span></p>
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<p><strong>Explanation:</strong></p>
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<p>In the range <code>[198, 202]</code>:</p>
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<ul>
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<li><code>198</code>: middle digit 9 is a peak, waviness = 1.</li>
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<li><code>201</code>: middle digit 0 is a valley, waviness = 1.</li>
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<li><code>202</code>: middle digit 0 is a valley, waviness = 1.</li>
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<li>All other numbers in the range have a waviness of 0.</li>
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</ul>
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<p>Thus, total waviness is <code>1 + 1 + 1 = 3</code>.</p>
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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">num1 = 4848, num2 = 4848</span></p>
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<p><strong>Output:</strong> <span class="example-io">2</span></p>
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<p><strong>Explanation:</strong></p>
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<p>Number <code>4848</code>: the second digit 8 is a peak, and the third digit 4 is a valley, giving a waviness of 2.</p>
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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 <= num1 <= num2 <= 10<sup>15</sup></code></li>
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</ul>
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