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73 lines
3.7 KiB
HTML
73 lines
3.7 KiB
HTML
<p>You are given an array of <strong>positive</strong> integers <code>nums</code>.</p>
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<p>Return the number of <span data-keyword="subarray-nonempty">subarrays</span> of <code>nums</code>, where the <strong>first</strong> and the <strong>last</strong> elements of the subarray are <em>equal</em> to the <strong>largest</strong> element in the subarray.</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">nums = [1,4,3,3,2]</span></p>
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<p><strong>Output:</strong> <span class="example-io">6</span></p>
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<p><strong>Explanation:</strong></p>
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<p>There are 6 subarrays which have the first and the last elements equal to the largest element of the subarray:</p>
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<ul>
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<li>subarray <code>[<strong><u>1</u></strong>,4,3,3,2]</code>, with its largest element 1. The first element is 1 and the last element is also 1.</li>
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<li>subarray <code>[1,<u><strong>4</strong></u>,3,3,2]</code>, with its largest element 4. The first element is 4 and the last element is also 4.</li>
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<li>subarray <code>[1,4,<u><strong>3</strong></u>,3,2]</code>, with its largest element 3. The first element is 3 and the last element is also 3.</li>
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<li>subarray <code>[1,4,3,<u><strong>3</strong></u>,2]</code>, with its largest element 3. The first element is 3 and the last element is also 3.</li>
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<li>subarray <code>[1,4,3,3,<u><strong>2</strong></u>]</code>, with its largest element 2. The first element is 2 and the last element is also 2.</li>
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<li>subarray <code>[1,4,<u><strong>3,3</strong></u>,2]</code>, with its largest element 3. The first element is 3 and the last element is also 3.</li>
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</ul>
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<p>Hence, we return 6.</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">nums = [3,3,3]</span></p>
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<p><strong>Output:</strong> <span class="example-io">6</span></p>
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<p><strong>Explanation:</strong></p>
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<p>There are 6 subarrays which have the first and the last elements equal to the largest element of the subarray:</p>
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<ul>
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<li>subarray <code>[<u><strong>3</strong></u>,3,3]</code>, with its largest element 3. The first element is 3 and the last element is also 3.</li>
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<li>subarray <code>[3,<strong><u>3</u></strong>,3]</code>, with its largest element 3. The first element is 3 and the last element is also 3.</li>
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<li>subarray <code>[3,3,<u><strong>3</strong></u>]</code>, with its largest element 3. The first element is 3 and the last element is also 3.</li>
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<li>subarray <code>[<strong><u>3,3</u></strong>,3]</code>, with its largest element 3. The first element is 3 and the last element is also 3.</li>
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<li>subarray <code>[3,<u><strong>3,3</strong></u>]</code>, with its largest element 3. The first element is 3 and the last element is also 3.</li>
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<li>subarray <code>[<u><strong>3,3,3</strong></u>]</code>, with its largest element 3. The first element is 3 and the last element is also 3.</li>
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</ul>
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<p>Hence, we return 6.</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">nums = [1]</span></p>
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<p><strong>Output:</strong> <span class="example-io">1</span></p>
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<p><strong>Explanation:</strong></p>
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<p>There is a single subarray of <code>nums</code> which is <code>[<strong><u>1</u></strong>]</code>, with its largest element 1. The first element is 1 and the last element is also 1.</p>
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<p>Hence, we return 1.</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 <= nums.length <= 10<sup>5</sup></code></li>
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<li><code>1 <= nums[i] <= 10<sup>9</sup></code></li>
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</ul>
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