871

class Solution {
public:
    int minRefuelStops(int target, int startFuel, vector<vector<int>>& stations) {
        int curMax = startFuel, stops=0, idx=0;
        priority_queue<int> pq;

        for(stops=0; curMax<target; stops++){
            while(idx<stations.size() && stations[idx][0] <= curMax)
                pq.push(stations[idx++][1]);
            if(pq.empty()) return -1;
            curMax += pq.top();
            pq.pop();
        }
        return stops;
    }
};