Compilare: user.cpp: In function ‘int main()’: user.cpp:26:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0, now; j < n; ++j){ ^ user.cpp:33:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (!i && j && j < n - 1) LP1 = (LP1 * base) % MOD; ^ user.cpp:43:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0, now, start; j < m; ++j){ ^ user.cpp:51:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j >= n){ /* Drop the last two values of line fron hash */ ^ user.cpp:56:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j >= n) /* make a new start and add it in hash */ ^ user.cpp:61:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if (j >= n - 1){ ^ 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("tetris2.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("tetris2.out", "w", stdout); ^ user.cpp:19:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &m); ^ user.cpp:22:26: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ", &M[i][j]); ^ user.cpp:24:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &n); ^ user.cpp:27:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &N[i][j]); ^