/in/foo.cc: In function 'int main()':
/in/foo.cc:77:10: warning: 'val' may be used uninitialized in this function [-Wmaybe-uninitialized]
   q.push(State(i,l,r,pos,val-sum[i-1]));//val-sum[i-1] 以i为左端点,右端点在l,r中的最大区间和
          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/in/foo.cc:29:93: warning: 'pos' may be used uninitialized in this function [-Wmaybe-uninitialized]
  State(int _from,int _l,int _r,int _pos,int _val):from(_from),l(_l),r(_r),pos(_pos),val(_val) {};
                                                                                             ^
/in/foo.cc:74:18: note: 'pos' was declared here
  for(int i=1,l,r,pos,val;i<=n-L+1;i++){
                  ^~~