Compilare: main.cpp: In function 'int main()': main.cpp:60:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<act[s].size();i++){ ~^~~~~~~~~~~~~~ main.cpp:73:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<act[s].size();i++){ ~^~~~~~~~~~~~~~ main.cpp:37:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("drum6.in","r",stdin); ^ main.cpp:38:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("drum6.out","w",stdout); ^ main.cpp:40:27: 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:44:33: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%c",&v[i][j]); ^