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"content": "<p>Given an integer array <code>nums</code> sorted in <strong>non-decreasing order</strong>, remove some duplicates <a href=\"https://en.wikipedia.org/wiki/In-place_algorithm\" target=\"_blank\"><strong>in-place</strong></a> such that each unique element appears <strong>at most twice</strong>. The <strong>relative order</strong> of the elements should be kept the <strong>same</strong>.</p>\n\n<p>Since it is impossible to change the length of the array in some languages, you must instead have the result be placed in the <strong>first part</strong> of the array <code>nums</code>. More formally, if there are <code>k</code> elements after removing the duplicates, then the first <code>k</code> elements of <code>nums</code> should hold the final result. It does not matter what you leave beyond the first <code>k</code> elements.</p>\n\n<p>Return <code>k</code><em> after placing the final result in the first </em><code>k</code><em> slots of </em><code>nums</code>.</p>\n\n<p>Do <strong>not</strong> allocate extra space for another array. You must do this by <strong>modifying the input array <a href=\"https://en.wikipedia.org/wiki/In-place_algorithm\" target=\"_blank\">in-place</a></strong> with O(1) extra memory.</p>\n\n<p><strong>Custom Judge:</strong></p>\n\n<p>The judge will test your solution with the following code:</p>\n\n<pre>\nint[] nums = [...]; // Input array\nint[] expectedNums = [...]; // The expected answer with correct length\n\nint k = removeDuplicates(nums); // Calls your implementation\n\nassert k == expectedNums.length;\nfor (int i = 0; i < k; i++) {\n assert nums[i] == expectedNums[i];\n}\n</pre>\n\n<p>If all assertions pass, then your solution will be <strong>accepted</strong>.</p>\n\n<p> </p>\n<p><strong>Example 1:</strong></p>\n\n<pre>\n<strong>Input:</strong> nums = [1,1,1,2,2,3]\n<strong>Output:</strong> 5, nums = [1,1,2,2,3,_]\n<strong>Explanation:</strong> Your function should return k = 5, with the first five elements of nums being 1, 1, 2, 2 and 3 respectively.\nIt does not matter what you leave beyond the returned k (hence they are underscores).\n</pre>\n\n<p><strong>Example 2:</strong></p>\n\n<pre>\n<strong>Input:</strong> nums = [0,0,1,1,1,1,2,3,3]\n<strong>Output:</strong> 7, nums = [0,0,1,1,2,3,3,_,_]\n<strong>Explanation:</strong> Your function should return k = 7, with the first seven elements of nums being 0, 0, 1, 1, 2, 3 and 3 respectively.\nIt does not matter what you leave beyond the returned k (hence they are underscores).\n</pre>\n\n<p> </p>\n<p><strong>Constraints:</strong></p>\n\n<ul>\n\t<li><code>1 <= nums.length <= 3 * 10<sup>4</sup></code></li>\n\t<li><code>-10<sup>4</sup> <= nums[i] <= 10<sup>4</sup></code></li>\n\t<li><code>nums</code> is sorted in <strong>non-decreasing</strong> order.</li>\n</ul>\n",
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