Compilare: main.cpp: In function 'void read()': main.cpp:82:10: warning: unused variable 'ok' [-Wunused-variable] bool ok; ^~ main.cpp: In function 'void dfs(int, int)': main.cpp:148:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < edges[node].size(); i++){ ~~^~~~~~~~~~~~~~~~~~~~ main.cpp: In function 'void Read(int&)': main.cpp:36:42: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(f, MAX, 1, IN), pos = 0; ^ main.cpp:41:42: warning: ignoring return value of 'size_t fread(void*, size_t, size_t, FILE*)', declared with attribute warn_unused_result [-Wunused-result] fread(f, MAX, 1, IN), pos = 0; ^ main.cpp: In function 'bool OK(int, int)': main.cpp:121:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ main.cpp: In function 'int main()': main.cpp:171:21: warning: 'node' may be used uninitialized in this function [-Wmaybe-uninitialized] dfs(node, 0); ^