[BNUZOJ][ACM][2014新生赛重现][现场]放课后茶会

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {

    /**
     * @param args
     */
    public static void main(String[] args) {
          Scanner sc = new Scanner(System.in);
          while(sc.hasNext()){
               int length = sc.nextInt();
               
               StringBuilder sb1 = new StringBuilder();
               StringBuilder sb2 = new StringBuilder();
               for(int i=0;i<length;i++){
                   sb1.append(sc.next());
               }
               
               for(int i=0;i<length;i++){
                   sb2.append(sc.next());
               }
               
                List<String> list = LCS(sb1.toString(),sb2.toString());
                
                if(list.size() > 0){
                    String result = list.get(0);
                    if(result.length() == sb1.length()){
                        System.out.println("^_^");
                    }else{
                        for(int i=0;i<result.length();i++){
                            System.out.print(result.charAt(i));
                            if(i<result.length()-1){
                                System.out.print(" ");
                            }
                        }
                        System.out.println();
                    }
                }else{
                    System.out.println("T_T");
                }
          }
          
    }
    
    
    public static List<String> LCS(String str1,String str2){
        List<String> result = new ArrayList<String>();
        int max = 0;
        
        int[][] dp = new int[str1.length()+1][str2.length()+1];
        
        for(int i=0;i<=str1.length();i++){
            dp[i][0] = 0;
        }
        
        for(int i=0;i<=str2.length();i++){
            dp[0][i] = 0;
        }
        
        for(int i=1;i<=str1.length();i++){
            for(int j=1;j<=str2.length();j++){
                if(str1.charAt(i-1) == str2.charAt(j-1)){
                    dp[i][j] = dp[i-1][j-1] + 1;
                    if(dp[i][j] >= max){
                        max = dp[i][j];
                        String s = str1.substring(i-max,i);
                        while(result.size() > 0 && result.get(result.size()-1).length() < s.length()){
                            result.remove(result.size()-1);
                        }
                        result.add(s);
                    }
                }else{
                    dp[i][j] = 0;
                }
            }
        }
        return result;
    }

}

利用LCS求出最长公共子串即可