3301. Maximize the Total Height of Unique Towers

You are given an array maximumHeight, where maximumHeight[i] denotes the maximum height the ith tower can be assigned.

Your task is to assign a height to each tower so that:

1. The height of the ith tower is a positive integer and does not exceed maximumHeight[i].
2. No two towers have the same height.

Return the maximum possible total sum of the tower heights. If it’s not possible to assign heights, return -1.

class Solution {
public:
    long long maximumTotalSum(vector<int>& maximumHeight) {
        sort(begin(maximumHeight), end(maximumHeight));
        long long res = maximumHeight.back();
        for(int i = maximumHeight.size() - 2; i >= 0; i--) {
            maximumHeight[i] = min(maximumHeight[i], maximumHeight[i+1] - 1);
            if(maximumHeight[i] <= 0) return -1;
            res += maximumHeight[i];
        }
        return res;
    }
};