Compilare: user.cpp: In function ‘int main()’: user.cpp:12:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("joctv.in","r",stdin); ^ user.cpp:13:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("joctv.out","w",stdout); ^ user.cpp:14:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ user.cpp:17:51: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&t[i][j]),sol=max(sol,t[i][j]); ^ user.cpp:30:61: warning: ‘l’ may be used uninitialized in this function [-Wmaybe-uninitialized] sol=max(sol,dp[j][maxcol]-dp[i-1][maxcol]-dp[j][maxcol-l]+dp[i-1][maxcol-l]); ^