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);
    }

516. Longest Palindromic Subsequence

https://leetcode.com/problems/longest-palindromic-subsequence/description/
    int longestPalindromeSubseq(string s) {
        int n = s.size();
        vector<vector<int>> dp(n, vector<int> (n, 0));
        for(int j=0; j<n; j++) {
            dp[j][j] = 1;
            for(int i=j-1; i>=0; i--) {
                if(s[i] == s[j]) dp[i][j] = dp[i+1][j-1] + 2;
                else dp[i][j] = max(dp[i+1][j], dp[i][j-1]);
            }
        }
        return dp[0][n-1];
    }