Compilare: main.cpp: In function 'void dfs_time(int)': main.cpp:47:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < G[x].size(); i++) ~~^~~~~~~~~~~~~ main.cpp: In function 'void dfs(int)': main.cpp:69:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i = 0; i < G[x].size(); i++) ~~^~~~~~~~~~~~~ main.cpp: In function 'void read_and_solve()': main.cpp:89:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &N, &M); ^ main.cpp:92:77: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] G[j].push_back(k), G[k].push_back(j), C[j].push_back(c), C[k].push_back(c); ^ main.cpp:94:42: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &query[i]), K[query[i]]++; ^ main.cpp: In function 'int main()': main.cpp:108:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("regat.in", "rt", stdin); ^ main.cpp:109:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("regat.out", "wt", stdout); ^