Compilare: main.cpp: In function 'int dial(int, int)': main.cpp:24:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j = 0 ; j < T[i].size() ; j ++) ~~^~~~~~~~~~~~~ main.cpp:28:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k = 0 ; k < G[u].size() ; k ++) ~~^~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:47:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("tollroads.in", "r", stdin); ^ main.cpp:48:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("tollroads.out", "w", stdout); ^ main.cpp:50:32: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &n, &m, &q); ^ main.cpp:53:36: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d", &x, &y, &z); ^ main.cpp:62:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &x, &t); ^