Kmp算法

public class Kmp {public static int[] next;public static void main(String[] args){System.out.println(match("abcabdaba", "aba"));}public static int match(String s,String t){if(t==null||s==null||t.length()>s.length()||t.length()==0||s.length()==0)return -1;else{int i = 0;int j = 0;getNext(t);while(i<s.length()&&j<t.length()){if(j==-1||s.charAt(i)==t.charAt(j)){i++;j++;}elsej = next[j];}if(j>=t.length())return i-t.length();elsereturn -1;}}public static void getNext(String t){int k = -1;int j = 0;next = new int[t.length()];next[0] = -1;while(j<t.length()-1){if(k==-1||t.charAt(k)==t.charAt(j)){++k;++j; if(t.charAt(j)!=t.charAt(k))next[j] = k;elsenext[j] = next[k];}elsek = next[k];}//for(int m:next)//{//System.out.print(m+" ");//}}}