Compilare: main.cpp: In function 'int main()': main.cpp:100:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<vals.size();i++) ~^~~~~~~~~~~~ main.cpp:90:34: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("engineer.in","r",stdin); ^ main.cpp:91:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("engineer.out","w",stdout); ^ main.cpp:92:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i",&n,&m); ^ main.cpp:96:54: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%i",&mat[i][j]),vals.pb(mat[i][j]); ^ main.cpp:111:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%i",&q); ^ main.cpp:114:51: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%i %i %i %i %i",&x1,&y1,&x2,&y2,&k); ^