• 這一題排序過後就變成簡單的不定長 sliding window 了,但要注意處理 duplicated number
class Solution {
public:
    int minOperations(vector<int>& nums) {
        sort(nums.begin(), nums.end());
        int left = 0, right = 0, n = nums.size(), res = 0;
        int curr = 0;
        while (right < n) {
            while (right < n - 1 && nums[right] == nums[right + 1]) right++;
            if (nums[right] - nums[left] > n-1) {
                while (left < n - 1 && nums[left] == nums[left + 1]) left++;
                left++;
                curr--;
            }
            right++;
            curr++;
            res = max(res, curr);
        }
        return n - curr;
    }
};