int minRefuelStops(int target, int startFuel, vector<vector<int>>& stations) {
if (startFuel >= target) return 0;
Heap bfs_q;
bfs_q.Insert(Stop{-1, startFuel});
auto n = 0;
Heap q;
unordered_map<int, bool> is_added;
while (!bfs_q.Empty()) {
auto s = bfs_q.Pop();
for(auto i = s.index+1; i < stations.size(); ++i) {
if (s.fuel >= stations[i][0]) {
if (is_added.find(i) != is_added.end()) {
//continue
break;
}
is_added[i] = true;
auto p = Stop{i, stations[i][1] + s.fuel};
if (p.fuel >= target) return n+1;
q.Insert(p);
} else {
break;
}
}
if (bfs_q.Empty() && !q.Empty()) {
bfs_q = q;
n++;
q.Clear();
is_added.clear();
}
}
return -1;
}
/** flush (clear) the cache */
inline void Flush()
{
m_map.Clear();
m_heap.Clear();
}
/** flush (clear) the cache */
FORCEINLINE void Flush()
{
m_map.Clear();
m_heap.Clear();
}