lc 最长连续序列

class Solution {
public:
    int longestConsecutive(vector<int>& nums) {
        int n = nums.size();
        if(n == 0) return 0;
        if(n == 1) return 1;
        set<int> s;
        for(int i = 0; i < n; i++) {
            s.insert(nums[i]);
        }
        int res = 1;
        for(int i = 0; i < n; i++) {
            if(s.find(nums[i]-1) == s.end()) {
                int cur_num = nums[i]+1;
                int cur_res = 1;
                while(s.find(cur_num) !=  s.end()) {
                    cur_num++;
                    cur_res++;
                    res = max(res, cur_res);
                }
            }
        }
        return res;
    }
};