26_remove_duplicates_from_sorted_array.cpp

#include <bits/stdc++.h>

using namespace std;

class Solution {
public:
    int removeDuplicates(vector<int>& nums) {
        int left = 0, right = 1;
        int n = nums.size();
        while (right < n) {
            if (nums[left] != nums[right]) {
                nums[++left] = nums[right];
            }
            ++right;
        }
        return ++left;
    }
};

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    vector<int> nums = {0, 0, 1, 1, 1, 2, 2, 3, 3, 4};
    Solution solve;
    int k = solve.removeDuplicates(nums);
    cout << "[";
    for (int i = 0; i < nums.size(); ++i) {
        if (i < k ) {
            cout << nums[i];
        } else {
            cout << "_";
        }
        cout << (i + 1 == nums.size() ? "]\n" : ",");
    }
    return 0;
}

/*
    ------------------
    Problem Statement:
    ------------------

    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.

    Consider the number of unique elements in nums to be k​​​​​​​​​​​​​​. After removing duplicates, return the number of unique elements k.

    The first k elements of nums should contain the unique numbers in sorted order. The remaining elements beyond index k - 1 can be ignored.

    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 * 10^4
    -100 <= nums[i] <= 100
    nums is sorted in non-decreasing order.
*/