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58 lines
2.7 KiB
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58 lines
2.7 KiB
HTML
<p>Given an integer array <code>nums</code> and an integer <code>val</code>, remove all occurrences of <code>val</code> in <code>nums</code> <a href="https://en.wikipedia.org/wiki/In-place_algorithm" target="_blank"><strong>in-place</strong></a>. The relative order of the elements may be changed.</p>
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<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>
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<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>
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<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>
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<p><strong>Custom Judge:</strong></p>
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<p>The judge will test your solution with the following code:</p>
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<pre>
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int[] nums = [...]; // Input array
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int val = ...; // Value to remove
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int[] expectedNums = [...]; // The expected answer with correct length.
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// It is sorted with no values equaling val.
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int k = removeElement(nums, val); // Calls your implementation
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assert k == expectedNums.length;
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sort(nums, 0, k); // Sort the first k elements of nums
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for (int i = 0; i < actualLength; i++) {
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assert nums[i] == expectedNums[i];
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}
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</pre>
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<p>If all assertions pass, then your solution will be <strong>accepted</strong>.</p>
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<p> </p>
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<p><strong>Example 1:</strong></p>
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<pre>
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<strong>Input:</strong> nums = [3,2,2,3], val = 3
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<strong>Output:</strong> 2, nums = [2,2,_,_]
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<strong>Explanation:</strong> Your function should return k = 2, with the first two elements of nums being 2.
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It does not matter what you leave beyond the returned k (hence they are underscores).
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</pre>
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<p><strong>Example 2:</strong></p>
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<pre>
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<strong>Input:</strong> nums = [0,1,2,2,3,0,4,2], val = 2
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<strong>Output:</strong> 5, nums = [0,1,4,0,3,_,_,_]
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<strong>Explanation:</strong> Your function should return k = 5, with the first five elements of nums containing 0, 0, 1, 3, and 4.
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Note that the five elements can be returned in any order.
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It does not matter what you leave beyond the returned k (hence they are underscores).
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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>0 <= nums.length <= 100</code></li>
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<li><code>0 <= nums[i] <= 50</code></li>
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<li><code>0 <= val <= 100</code></li>
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</ul>
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