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+<h2><a href="https://leetcode.com/problems/total-waviness-of-numbers-in-range-i">4057. Total Waviness of Numbers in Range I</a></h2><h3>Medium</h3><hr><p>You are given two integers <code>num1</code> and <code>num2</code> representing an <strong>inclusive</strong> range <code>[num1, num2]</code>.</p>
+
+<p>The <strong>waviness</strong> of a number is defined as the total count of its <strong>peaks</strong> and <strong>valleys</strong>:</p>
+
+<ul>
+	<li>A digit is a <strong>peak</strong> if it is <strong>strictly greater</strong> than both of its immediate neighbors.</li>
+	<li>A digit is a <strong>valley</strong> if it is <strong>strictly less</strong> than both of its immediate neighbors.</li>
+	<li>The first and last digits of a number <strong>cannot</strong> be peaks or valleys.</li>
+	<li>Any number with fewer than 3 digits has a waviness of 0.</li>
+</ul>
+Return the total sum of waviness for all numbers in the range <code>[num1, num2]</code>.
+<p>&nbsp;</p>
+<p><strong class="example">Example 1:</strong></p>
+
+<div class="example-block">
+<p><strong>Input:</strong> <span class="example-io">num1 = 120, num2 = 130</span></p>
+
+<p><strong>Output:</strong> <span class="example-io">3</span></p>
+
+<p><strong>Explanation:</strong></p>
+In the range <code>[120, 130]</code>:
+
+<ul>
+	<li><code>120</code>: middle digit 2 is a peak, waviness = 1.</li>
+	<li><code>121</code>: middle digit 2 is a peak, waviness = 1.</li>
+	<li><code>130</code>: middle digit 3 is a peak, waviness = 1.</li>
+	<li>All other numbers in the range have a waviness of 0.</li>
+</ul>
+
+<p>Thus, total waviness is <code>1 + 1 + 1 = 3</code>.</p>
+</div>
+
+<p><strong class="example">Example 2:</strong></p>
+
+<div class="example-block">
+<p><strong>Input:</strong> <span class="example-io">num1 = 198, num2 = 202</span></p>
+
+<p><strong>Output:</strong> <span class="example-io">3</span></p>
+
+<p><strong>Explanation:</strong></p>
+In the range <code>[198, 202]</code>:
+
+<ul>
+	<li><code>198</code>: middle digit 9 is a peak, waviness = 1.</li>
+	<li><code>201</code>: middle digit 0 is a valley, waviness = 1.</li>
+	<li><code>202</code>: middle digit 0 is a valley, waviness = 1.</li>
+	<li>All other numbers in the range have a waviness of 0.</li>
+</ul>
+
+<p>Thus, total waviness is <code>1 + 1 + 1 = 3</code>.</p>
+</div>
+
+<p><strong class="example">Example 3:</strong></p>
+
+<div class="example-block">
+<p><strong>Input:</strong> <span class="example-io">num1 = 4848, num2 = 4848</span></p>
+
+<p><strong>Output:</strong> <span class="example-io">2</span></p>
+
+<p><strong>Explanation:</strong></p>
+
+<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>
+</div>
+
+<p>&nbsp;</p>
+<p><strong>Constraints:</strong></p>
+
+<ul>
+	<li><code>1 &lt;= num1 &lt;= num2 &lt;= 10<sup>5</sup></code></li>
+</ul>