  We present an online algorithm to deal with pattern matching in strings. The
problem we investigate is commonly known as string matching with mismatches in
which the objective is to report the number of characters that match when a
pattern is aligned with every location in the text. The novel method we propose
is based on the frequencies of individual characters in the pattern and the
text. The algorithm consumes minimal space in the form of simple arrays, which
reduces the cost overhead to maintain the complex data structures such as
suffix trees or automaton.
