Compilare: user.cpp: In function ‘int main()’: user.cpp:68:42: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<=3*rad && dq[x1][j].size()<y1;j++) ^ user.cpp:72:43: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=0;j<=3*rad && dq[x2][j].size()<y2;j++) ^ user.cpp:52:25: warning: unused variable ‘t’ [-Wunused-variable] int i,j,x1,x2,y1,y2,t,val,l,x; ^ user.cpp:50:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("grid.in","r",stdin); ^ user.cpp:51:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("grid.out","w",stdout); ^ user.cpp:53:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&k); ^ user.cpp:66:38: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&x1,&y1,&x2,&y2); ^