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			41 lines
		
	
	
		
			1.5 KiB
		
	
	
	
		
			HTML
		
	
	
	
	
	
<p>You are given a <strong>0-indexed</strong>, <strong>strictly increasing</strong> integer array <code>nums</code> and a positive integer <code>diff</code>. A triplet <code>(i, j, k)</code> is an <strong>arithmetic triplet</strong> if the following conditions are met:</p>
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<ul>
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	<li><code>i < j < k</code>,</li>
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	<li><code>nums[j] - nums[i] == diff</code>, and</li>
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	<li><code>nums[k] - nums[j] == diff</code>.</li>
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</ul>
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<p>Return <em>the number of unique <strong>arithmetic triplets</strong>.</em></p>
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<p> </p>
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<p><strong class="example">Example 1:</strong></p>
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<pre>
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<strong>Input:</strong> nums = [0,1,4,6,7,10], diff = 3
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<strong>Output:</strong> 2
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<strong>Explanation:</strong>
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(1, 2, 4) is an arithmetic triplet because both 7 - 4 == 3 and 4 - 1 == 3.
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(2, 4, 5) is an arithmetic triplet because both 10 - 7 == 3 and 7 - 4 == 3. 
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</pre>
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<p><strong class="example">Example 2:</strong></p>
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<pre>
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<strong>Input:</strong> nums = [4,5,6,7,8,9], diff = 2
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<strong>Output:</strong> 2
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<strong>Explanation:</strong>
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(0, 2, 4) is an arithmetic triplet because both 8 - 6 == 2 and 6 - 4 == 2.
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(1, 3, 5) is an arithmetic triplet because both 9 - 7 == 2 and 7 - 5 == 2.
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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>3 <= nums.length <= 200</code></li>
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	<li><code>0 <= nums[i] <= 200</code></li>
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	<li><code>1 <= diff <= 50</code></li>
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	<li><code>nums</code> is <strong>strictly</strong> increasing.</li>
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</ul>
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