class Solution { public: int mincostTickets(vector<int>& days, vector<int>& costs) { int ans = 0; queue<pair<int, int>> last7; queue<pair<int, int>> last30; for (int day : days) { while (!last7.empty() && last7.front().first + 7 <= day) last7.pop(); while (!last30.empty() && last30.front().first + 30 <= day) last30.pop(); last7.emplace(day, ans + costs[1]); last30.emplace(day, ans + costs[2]); ans = min({ans + costs[0], last7.front().second, last30.front().second}); } return ans; } };