/in/foo.cc: In function 'long long int calculate_matrix_pow_dp(int)':
/in/foo.cc:22:34: warning: operation on 'k' may be undefined [-Wsequence-point]
    x[k]=calculate_matrix_pow_dp(k>>=1);
                                 ~^~~~
/in/foo.cc:32:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^
/in/foo.cc: In function 'void setup()':
/in/foo.cc:34:38: warning: iteration 500000 invokes undefined behavior [-Waggressive-loop-optimizations]
  for(int i=1;i<=MAX;i++) traceback[i]=1;
                          ~~~~~~~~~~~~^~
/in/foo.cc:34:15: note: within this loop
  for(int i=1;i<=MAX;i++) traceback[i]=1;
              ~^~~~~