[LeetCode] 26. Remove Duplicates from Sorted Array

Given an integer array nums sorted in non-decreasing order, remove the duplicates in-place such that each unique element appears only once. The relative order of the elements should be kept the same.

Since it is impossible to change the length of the array in some languages, you must instead have the result be placed in the first part of the array nums. More formally, if there are k elements after removing the duplicates, then the first k elements of nums should hold the final result. It does not matter what you leave beyond the first k elements.

Return k after placing the final result in the first k slots of nums.

Do not allocate extra space for another array. You must do this by modifying the input array in-place with O(1) extra memory.

Custom Judge:

The judge will test your solution with the following code:

int[] nums = [...]; // Input array
int[] expectedNums = [...]; // The expected answer with correct length

int k = removeDuplicates(nums); // Calls your implementation

assert k == expectedNums.length;
for (int i = 0; i < k; i++) {
    assert nums[i] == expectedNums[i];
}

If all assertions pass, then your solution will be accepted.

 

Example 1:

Input: nums = [1,1,2]
Output: 2, nums = [1,2,_]
Explanation: Your function should return k = 2, with the first two elements of nums being 1 and 2 respectively.
It does not matter what you leave beyond the returned k (hence they are underscores).

Example 2:

Input: nums = [0,0,1,1,1,2,2,3,3,4]
Output: 5, nums = [0,1,2,3,4,_,_,_,_,_]
Explanation: Your function should return k = 5, with the first five elements of nums being 0, 1, 2, 3, and 4 respectively.
It does not matter what you leave beyond the returned k (hence they are underscores).

 

Constraints:

• 1 <= nums.length <= 3 * 104
• -100 <= nums[i] <= 100
• nums is sorted in non-decreasing order.

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주어진 숫자열에서 중복을 제거하는 문제로 조건에 따르면 non-decreasing으로 정렬되있는 사실을 알 수 있다.

이를 이용하여 index를 이용하여 연속된 두 수의 값이 동일한지 여부를 체크한 후 동일한 경우 삭제한다.

 

class Solution:
   def removeDuplicates(self, nums):
       i = 0
       while i < len(nums)-1:
           if nums[i] == nums[i+1]:
               del nums[i]
           else:
               i += 1
       return len(nums)

 

 

문제 출처 :https://leetcode.com/problems/remove-duplicates-from-sorted-array/

Remove Duplicates from Sorted Array - LeetCode

Github : https://github.com/kkkkang1009/leetcode/blob/master/leetcode_26.py

GitHub - kkkkang1009/leetcode: leetcode