Compilare: user.cpp: In function ‘int solve()’: user.cpp:57:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(sol.size()+nr!=n*m) return 0; ^ user.cpp: In function ‘void read()’: user.cpp:21:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n",&n,&m); ^ user.cpp:25:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(scanf("%c",&ch);ch==' ' || ch=='\n';scanf("%c",&ch)); ^ user.cpp:25:10: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(scanf("%c",&ch);ch==' ' || ch=='\n';scanf("%c",&ch)); ^ user.cpp:28:10: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for(nrc=0;ch>='0' && ch<='9';scanf("%c",&ch)) ^ user.cpp: In function ‘int main()’: user.cpp:71:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("traseu2.in","r",stdin); ^ user.cpp:72:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("traseu2.out","w",stdout); ^