class Solution {
public:
    /**
     * max increasing subsequence
     * @param arr int整型vector the array
     * @return int整型
     */
int MLS(vector<int>& arr) {
        // write code here
        if(arr.empty()) {
            return 0;
        }
        int longest=1, cnt = 1;
        vector<int>dp(arr.size(), 1);
        sort(arr.begin(),arr.end());
        for(int i=1;i<arr.size();++i){
            if (arr[i] == arr[i-1]) {
                continue;
            }
            if (arr[i] - arr[i - 1] == 1) {
                cnt ++;
            }  else {
                cnt = 1;
            }
              
            longest=max(longest, cnt);
        }
        return longest;
    }

};