EXACT STRING MATCHING ALGORITHMS
String-matching algorithms of the present book work as follows. They scan the text with the help of a window which size is generally equal to m. They first align the left ends of the window and the text, then compare the characters of the window with the characters of the pattern – this specific work is called an attempt – and after a whole match of the pattern or after a mismatch they shift the window to the right. They repeat the same procedure again until the right end of the window goes beyond the right end of the text. This mechanism is usually called the sliding window mechanism. We associate each attempt with the position j in the text when the window is positioned on y[j .. j+m-1].