Compilare: main.cpp: In function 'bool exist(int)': main.cpp:13:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i< g[key].size();i++) ~^~~~~~~~~~~~~~~ main.cpp:13:3: warning: this 'for' clause does not guard... [-Wmisleading-indentation] for(int i=0;i< g[key].size();i++) ^~~ main.cpp:15:9: note: ...this statement, but the latter is misleadingly indented as if it is guarded by the 'for' return ok; ^~~~~~ main.cpp:12:7: warning: unused variable 'i' [-Wunused-variable] int i; ^