foo.c: In function 'main':
foo.c:11:20: warning: format '%d' expects a matching 'int *' argument [-Wformat=]
         scanf("%d %d",&w[i]);
                   ~^
foo.c:15:20: error: 'c' undeclared (first use in this function)
     for(j=sum/2;j>=c[i];j--)
                    ^
foo.c:15:20: note: each undeclared identifier is reported only once for each function it appears in
foo.c:7:5: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&m);
     ^~~~~~~~~~~~~~
foo.c:11:9: warning: ignoring return value of 'scanf', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d %d",&w[i]);
         ^~~~~~~~~~~~~~~~~~~~

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。