std::vector<RRTNode *> st1(RRTNode *init, RRTNode *goal);
std::vector<RRTNode *> st2(RRTNode *init, RRTNode *goal);
std::vector<RRTNode *> st3(RRTNode *init, RRTNode *goal);
+std::vector<RRTNode *> st3(RRTNode *init, RRTNode *goal, float step);
std::vector<RRTNode *> st4(RRTNode *init, RRTNode *goal);
#endif