Word Partitioning

Given and array A[1 . . . n] of characters, we say A can be word partitioned if it can be decomposed into disjoint substrings, where each substring is an English word. For example, the string ARTISTOIL can be word partitioned as ARTIST OIL, or as ART IS TOIL. You are given a subroutine IsW ord(i, j), which for i j returns True if A[i . . . j] is a word, and False otherwise. Using this subroutine, compute the number of distinct ways in which A can be word partitioned.