foo.cc: In function 'int main()':
foo.cc:19:40: warning: unused variable 'd' [-Wunused-variable]
  int m,i,i1,i2,i3,i4,i5,least,less,a,c,d;
                                        ^
foo.cc: In function 'void SelectSmall(int*, int&, int&, int)':
foo.cc:13:13: warning: 'a' may be used uninitialized in this function [-Wmaybe-uninitialized]
   if(n[i2]<y&&i2!=a)
      ~~~~~~~^~~~~~~
foo.cc: In function 'int main()':
foo.cc:13:13: warning: 'a' may be used uninitialized in this function [-Wmaybe-uninitialized]
   if(n[i2]<y&&i2!=a)
      ~~~~~~~^~~~~~~
foo.cc:6:30: note: 'a' was declared here
  int x=20001;int y=20001;int a;
                              ^
foo.cc:33:19: warning: 'less' may be used uninitialized in this function [-Wmaybe-uninitialized]
    if(n[i2]==least||n[i2]==less)
       ~~~~~~~~~~~~^~~~~~~~~~~~~
foo.cc:29:14: warning: 'least' may be used uninitialized in this function [-Wmaybe-uninitialized]
   b[i1]=least+less;
         ~~~~~^~~~~

自豪的采用jd5进行评测(github.com/masnn/jd5)