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80 lines
2.4 KiB
Python
80 lines
2.4 KiB
Python
"""
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80. Remove Duplicates from Sorted Array II
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Difficulty: Medium
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https://leetcode.com/problems/remove-duplicates-from-sorted-array-ii/
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──────────────────────────────────────────────────
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Given an integer array nums sorted in non-decreasing order, remove
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some duplicates in-place such that each unique element appears at most
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twice. The relative order of the elements should be kept the same.
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Since it is impossible to change the length of the array in some
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languages, you must instead have the result be placed in the first
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part of the array nums. More formally, if there are k elements after
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removing the duplicates, then the first k elements of nums should hold
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the final result. It does not matter what you leave beyond the first k
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elements.
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Return k after placing the final result in the first k slots of nums.
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Do not allocate extra space for another array. You must do this by
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modifying the input array in-place with O(1) extra memory.
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Custom Judge:
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The judge will test your solution with the following code:
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int[] nums = [...]; // Input array
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int[] expectedNums = [...]; // The expected answer with correct length
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int k = removeDuplicates(nums); // Calls your implementation
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assert k == expectedNums.length;
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for (int i = 0; i < k; i++) {
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assert nums[i] == expectedNums[i];
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}
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If all assertions pass, then your solution will be accepted.
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Example 1:
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Input: nums = [1,1,1,2,2,3]
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Output: 5, nums = [1,1,2,2,3,_]
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Explanation: Your function should return k = 5, with the first five
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elements of nums being 1, 1, 2, 2 and 3 respectively.
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It does not matter what you leave beyond the returned k (hence they
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are underscores).
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Example 2:
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Input: nums = [0,0,1,1,1,1,2,3,3]
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Output: 7, nums = [0,0,1,1,2,3,3,_,_]
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Explanation: Your function should return k = 7, with the first seven
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elements of nums being 0, 0, 1, 1, 2, 3 and 3 respectively.
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It does not matter what you leave beyond the returned k (hence they
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are underscores).
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Constraints:
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• 1 <= nums.length <= 3 * 10^4
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• -10^4 <= nums[i] <= 10^4
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• nums is sorted in non-decreasing order.
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"""
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class Solution:
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def removeDuplicates(self, nums: list[int]) -> int:
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slow = 0
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for fast in range(len(nums)):
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if slow < 2 or nums[fast] != nums[slow - 2]:
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nums[slow] = nums[fast]
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slow += 1
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return slow
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