740. Delete and Earn

https://leetcode.com/problems/delete-and-earn/description/
    int deleteAndEarn(vector<int>& nums) {
        vector<int> ns(100001, 0);
        for(int i: nums) ns[i]++;
        int skip = 0, keep = 0;
        for(int i=1; i<ns.size(); i++) {
            int keepi = skip + i * ns[i];
            skip = max(keep, skip);
            keep = keepi;
        }
        return max(keep, skip);
    }