CCF字符串匹配(Java)

KMP在Java中的实现indexOf()

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;
public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        String s = br.readLine();
        int c = Integer.parseInt(br.readLine());
        int m = Integer.parseInt(br.readLine());
        if(c==0) s = s.toLowerCase();
        String ps = "",psc = "";
        while(m-->0) {
            ps = br.readLine();
            if(c==0) {
                psc = ps.toLowerCase();
            }else {
                psc = ps;
            }
            if(process(psc,s)) {
                bw.write(ps+"\n");
            }
        }
        bw.flush();
    }

    private static boolean process(String psc, String s) {
        return psc.indexOf(s)!=-1;
    }
}

再补上一个KMP

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(System.out));
        String s = br.readLine();
        int c = Integer.parseInt(br.readLine());
        int m = Integer.parseInt(br.readLine());
        if(c==0) s = s.toLowerCase();
        String ps = "",psc = "";
        while(m-->0) {
            ps = br.readLine();
            if(c==0) {
                psc = ps.toLowerCase();
            }else {
                psc = ps;
            }
//          if(psc.indexOf(s)!=-1) bw.write(ps+"\n");
            if(KMP(psc,s)) bw.write(ps+"\n");
        }
        bw.flush();
    }

    private static boolean KMP(String psc, String s) {
        char[] a1 = (" "+s).toCharArray();
        char[] a2 = (" "+psc).toCharArray();
        int len = s.length();
        int n = psc.length(); 
        int ne[] = new int[len+1];
        ne[1] = 0;
        for(int i = 2, j = 0;i <= len ; i ++) {
            while(j!=0&&a1[i]!=a1[j+1]) j = ne[j];
            if(a1[i]==a1[j+1]) j++;
            ne[i] = j;
        }
        
        for(int i = 1,j = 0; i <= n;i++) {
            while(j!=0&&a2[i]!=a1[j+1]) j = ne[j];
            if(a2[i]==a1[j+1]) j++;
            if(j==len) {
                return true;
            }
        }
        return false;
    }
    
}