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			40 lines
		
	
	
		
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			40 lines
		
	
	
		
			1.5 KiB
		
	
	
	
		
			HTML
		
	
	
	
	
	
<p>You are given an integer array <code>nums</code> of length <code>n</code> where <code>nums</code> is a permutation of the numbers in the range <code>[0, n - 1]</code>.</p>
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<p>You should build a set <code>s[k] = {nums[k], nums[nums[k]], nums[nums[nums[k]]], ... }</code> subjected to the following rule:</p>
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<ul>
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	<li>The first element in <code>s[k]</code> starts with the selection of the element <code>nums[k]</code> of <code>index = k</code>.</li>
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	<li>The next element in <code>s[k]</code> should be <code>nums[nums[k]]</code>, and then <code>nums[nums[nums[k]]]</code>, and so on.</li>
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	<li>We stop adding right before a duplicate element occurs in <code>s[k]</code>.</li>
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</ul>
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<p>Return <em>the longest length of a set</em> <code>s[k]</code>.</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 = [5,4,0,3,1,6,2]
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<strong>Output:</strong> 4
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<strong>Explanation:</strong> 
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nums[0] = 5, nums[1] = 4, nums[2] = 0, nums[3] = 3, nums[4] = 1, nums[5] = 6, nums[6] = 2.
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One of the longest sets s[k]:
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s[0] = {nums[0], nums[5], nums[6], nums[2]} = {5, 6, 2, 0}
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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 = [0,1,2]
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<strong>Output:</strong> 1
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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>1 <= nums.length <= 10<sup>5</sup></code></li>
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	<li><code>0 <= nums[i] < nums.length</code></li>
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	<li>All the values of <code>nums</code> are <strong>unique</strong>.</li>
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</ul>
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