foo.cc: In function 'int jia(int*, int*)':
foo.cc:12:11: warning: operation on 'lenc' may be undefined [-Wsequence-point]
         a[++lenc]=a[lenc]+b[lenc]+x;
           ^~~~~~
foo.cc:12:11: warning: operation on 'lenc' may be undefined [-Wsequence-point]
foo.cc:18:1: warning: no return statement in function returning non-void [-Wreturn-type]
 }
 ^
foo.cc: In function 'int main()':
foo.cc:29:9: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
         if (kk==0) y=minn;int tot=0;
         ^~
foo.cc:29:27: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
         if (kk==0) y=minn;int tot=0;
                           ^~~
foo.cc:21:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d",&k,&w);
     ~~~~~^~~~~~~~~~~~~~

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