Compilare: user.cpp: In function ‘int main()’: user.cpp:28:37: warning: narrowing conversion of ‘i’ from ‘int’ to ‘short int’ inside { } [-Wnarrowing] v1[a[i][j]].push_back({i, j}); ^ user.cpp:28:37: warning: narrowing conversion of ‘j’ from ‘int’ to ‘short int’ inside { } [-Wnarrowing] user.cpp:15:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sarpe2.in", "r", stdin); ^ user.cpp:16:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sarpe2.out", "w", stdout); ^ user.cpp:18:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &m); ^ user.cpp:20:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); ^ user.cpp:25:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a[i][j]); ^