如何使用java实现KMP算法

public class KMP {
    public static int[] computePrefixFunction(String pattern) {
        int m = pattern.length();
        int[] pi = new int[m];
        int k = 0;
        for (int i = 1; i < m; i++) {
            while (k > 0 && pattern.charAt(k) != pattern.charAt(i)) {
                k = pi[k - 1];
            }
            if (pattern.charAt(k) == pattern.charAt(i)) {
                k++;
            }
            pi[i] = k;
        }
        return pi;
    }

    public static int search(String text, String pattern) {
        int n = text.length();
        int m = pattern.length();
        int[] pi = computePrefixFunction(pattern);
        int q = 0;
        for (int i = 0; i < n; i++) {
            while (q > 0 && pattern.charAt(q) != text.charAt(i)) {
                q = pi[q - 1];
            }
            if (pattern.charAt(q) == text.charAt(i)) {
                q++;
            }
            if (q == m) {
                return i - m + 1;
            }
        }
        return -1;
    }

    public static void main(String[] args) {
        String text = "ababababacaba";
        String pattern = "bac";
        int index = search(text, pattern);
        if (index != -1) {
            System.out.println("Pattern found at index " + index);
        } else {
            System.out.println("Pattern not found");
        }
    }
}