Compilare: user.cpp: In function ‘void read()’: user.cpp:46:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<robot.size(); ++i) ^ user.cpp: In function ‘void convex_hull(std::vector<std::pair<int, int> >&)’: user.cpp:82:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<poly.size(); ++i) ^ user.cpp:96:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<poly.size(); ++i) ^ user.cpp: In function ‘void get_newob()’: user.cpp:113:36: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j<ob[i].size(); ++j) ^ user.cpp:114:40: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int k=0; k<robot.size(); ++k) ^ user.cpp: In function ‘void build_graph()’: user.cpp:128:39: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j=0; j<newob[i].size(); ++j) ^ user.cpp: In function ‘bool segment_polygon_intersection(const std::pair<int, int>&, const std::pair<int, int>&, const std::vector<std::pair<int, int> >&)’: user.cpp:197:18: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if (ok1 == 0 && ok2 == 0 || ok1 == 1 || ok2 == 1) ^ user.cpp: In function ‘void dijkstra()’: user.cpp:226:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=1; i<graph.size(); ++i) ^ user.cpp:243:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<graph.size(); ++i) ^