983

class Solution {
public:
    int mincostTickets(vector<int>& days, vector<int>& cost) {
        vector<bool> day(366, false);
        for(auto d: days)
            day[d] = true;

        int dp[366];
        dp[0] = 0;
        for(int i=1; i<=365; i++)
            if(!day[i])
                dp[i] = dp[i-1];
            else
                dp[i] = min({cost[0]+dp[i-1], cost[1]+dp[max(0, i-7)], cost[2]+dp[max(0, i-30)]});
        return dp[365];
    }
};