/in/foo.cc: In function 'int main()':
/in/foo.cc:31:36: warning: narrowing conversion of 'y[i]' from 'int' to 'double' inside { } [-Wnarrowing]
   if(i!=1)a[++tot]=(node){i-1,i,y[i]};
                                 ~~~^
/in/foo.cc:36:40: warning: narrowing conversion of 'y[i]' from 'int' to 'double' inside { } [-Wnarrowing]
   if(i!=1)a[++tot]=(node){i+n-1,i+n,y[i]};
                                     ~~~^