KMP algorithm and kmp algorithm code

KMP algorithm and kmp algorithm code

Self-written KMP algorithm for hands-on

import java.io.BufferedReader;import java.io.IOException;import java.io.InputStreamReader;/** * Created by niweimin on 2014/12/23. */public class KmpMatch {    public String patten;    public int matchTimes;    public KmpMatch(String patten){        this.patten = patten;    }    public static void main(String [] args){        System.out.print("Please input the patten string:");        String patten = "", target = "";        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));        try {            patten = reader.readLine();        } catch (IOException e) {            e.printStackTrace();        }        System.out.print("Please input the target string:");        try {            target = reader.readLine();        } catch (IOException e) {            e.printStackTrace();        }        KmpMatch match = new KmpMatch(patten);        if(match.findMatch(target)){            System.out.println("Find! Match Times: " + match.matchTimes);        }else{            System.out.println("Not Find!");        }    }    private int[] genNextTable(){        int [] table = new int[patten.length()];        table [0] = -1;        for(int i = 1; i < table.length; i++){            table [i] = next(i);        }        return table;    }    private int next(int j) {        int max = 0;        for(int i = 1; i < j - 1; i++){            if(patten.substring(0, i).equals(patten.substring(j - i, j))){                max = i;            }        }        return max;    }    public boolean findMatch(String target){        int  j = 0, next = 0, start = 0, i = start;        int [] table = genNextTable();        while(patten.length() - j <= target.length() - i) {            while (patten.charAt(j) == target.charAt(i)) {                matchTimes++;                if (j == patten.length() - 1) {                    return true;                }                i++;                j++;            }            matchTimes++;            next = table[j];            start = start + j - next;            i = start + next;            j = Math.max(0, next);        }        return false;    }}