Compilare: main.cpp: In function 'void solve()': main.cpp:58:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i = 0; i < M[dist].size(); ++i) ~~^~~~~~~~~~~~~~~~ main.cpp: In function 'int main()': main.cpp:100:33: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("alpin.in", "r", stdin); ^ main.cpp:101:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("alpin.out", "w", stdout); ^ main.cpp: In function 'void read()': main.cpp:26:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &n); ^ main.cpp:31:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &A[i][j]); ^ main.cpp: In function 'void solve()': main.cpp:55:6: warning: 'maxj' may be used uninitialized in this function [-Wmaybe-uninitialized] int maxj; ^~~~ main.cpp:54:6: warning: 'maxi' may be used uninitialized in this function [-Wmaybe-uninitialized] int maxi; ^~~~