Leetcode 128 *

class Solution {
public:
    int longestConsecutive(vector<int>& nums) {
        int res = ;
        unordered_map<int,int> m;
        for(int i=;i < nums.size();i++){
            if(m.count(nums[i])) continue;
            int left = (m.count(nums[i]-) >  ? m[nums[i]-]:);
            int right = (m.count(nums[i]+) >  ? m[nums[i]+]:);
            int sum = left + right + ;
            m[nums[i]] = sum; // 为什么要加这个，不是改变两端么
            res = max(res,sum);
            m[nums[i]-left] = sum;
            m[nums[i]+right] = sum;
        }
        return res;
    }
};

还有bug，太晚了不想想了，下次再补