leetcode 594最长和谐子序列

class Solution {
public:
    int findLHS(vector<int>& nums) {
        int res=0;
        map<int,int> m;
        for(auto num:nums) ++m[num];
        for(auto a:m){
            if (m.count(a.first+1)){
                res=max(res,m[a.first]+m[a.first+1]);
            }
        }
        return res;
    }
};