1014. Best Sightseeing Pair

You are given an integer array values where values[i] represents the value of the ith sightseeing spot. Two sightseeing spots i and j have a distance j - i between them.

The score of a pair (i < j) of sightseeing spots is values[i] + values[j] + i - j: the sum of the values of the sightseeing spots, minus the distance between them.

Return the maximum score of a pair of sightseeing spots.

class Solution {
public:
    int maxScoreSightseeingPair(vector<int>& values) {
        int res = 0, ma = values[0] - 1;
        for(int i = 1; i < values.size(); i++, ma--) {
            res = max(res, values[i] + ma);
            ma = max(ma, values[i]);
        }
        return res;
    }
};