Compilare: user.cpp: In function ‘int main()’: user.cpp:107:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < L[c].size(); i ++ ) { ^ user.cpp:113:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < L[c].size(); i ++ ) { ^ user.cpp:141:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 0; i < L[c].size(); i ++ ) { ^ user.cpp:73:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "unlock.in" , "r", stdin ); ^ user.cpp:74:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen( "unlock.out", "w", stdout ); ^ user.cpp:76:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d", &T ); ^ user.cpp:78:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d %d %d", &N, &M, &P ); nr = 0; ^ user.cpp:82:36: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf( "%d", &A[i][j] ); ^