bool isRobotBounded(string instructions) {
for(auto c: instructions)
// 0,4,-4 stands for UP, 1，-3 stands for Right, -1,3 stands for Left, 2 and -2 stands for Down;
pos.second +=(direc==0) - (direc ==2 || direc ==-2);
pos.first += (direc==1)+(direc==-3) -(direc ==-1)-(direc==3);
// cout<<pos.first<<" "<<pos.second<<endl;
if( pos.first==0 && pos.second ==0) return true;
// cout<<direc<<" "<<pos.first<<" "<<pos.second<<endl;