text: Stores the maximum prefix sum
code: int maxPref = V . get ( 2 * N - 1 ) ; curr = V . get ( 0 ) ; for ( int i = 1 ; i < 2 * N ; i ++ ) { curr += V . get ( i ) ; maxPref = Math . max ( maxPref , curr ) ; } curr = V . get ( 2 * N - 1 ) ; for ( int i = 2 * N - 2 ; i >= 0 ; i -- ) { curr += V . get ( i ) ; maxSuf = Math . max ( maxSuf , curr ) ; } curr = V . get ( 0 ) ;