USACO试题beads的两种解法

package Karl.Water;

/*
LANG: JAVA
TASK: beads
*/


import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.PrintWriter;
import java.util.LinkedList;

public class beads {

  /**
   * @param args
   */
  public static void main(String[] args) {
    // TODO Auto-generated method stub
    try {
      BufferedReader br = new BufferedReader(new FileReader("beads.in"));
      PrintWriter pw = new PrintWriter (new FileWriter("beads.out"));

      int length = Integer.parseInt(br.readLine());
      String temp = br.readLine();
      LinkedList<Character> necklace = new LinkedList<Character>();
      for (int i=0;i<length;i++) {
        necklace.add(temp.charAt(i));
      }

      int max = 0;
      for (int i=0;i<length;i++) {
        char remove = necklace.removeFirst();
        char first = necklace.getFirst();
        int position = 0;
        necklace.addLast(remove);

        int result = 0;
        boolean allW = false;
        if (necklace.getFirst()=='w'){
          int end1 = find(necklace,0,length,0); 
          result = end1 + 1;
          if (end1<necklace.size()-1){
            int end2 = find (necklace,end1+1,length,0);
            first = necklace.get(end2);
            position = end2;
            result = result + end2 - end1;
          }else {
            allW = true;
          }
        } else {
          int end = find(necklace,0,length,0);
          position = end ;
          result = result + end + 1;
        }
        if (!allW){
          if (necklace.getLast()=='w') {
            int end1 = find(necklace, length-1,position,1);
            int end2 = find(necklace,end1-1,position,1);

            if (necklace.get(end2)==first){
              result = result ;
            }else {
              result = result + length - end1;
              result = result + end1 - end2 ;
            }
          }else {
            if (necklace.getLast()==first){
              result = result; 
            }else {
              int end = find(necklace,length-1,position,1);
              result = result + length - end ;  
            }
          }
        }
        if (result >=max){
          max = result;
        }
      }
      pw.println(max);
      pw.close();
      br.close();
    } catch (Exception e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
    }
  }

  public static int find(LinkedList<Character> necklace,int startPoint ,int endPoint,int direction){
    if (direction ==0 ){
      int i=startPoint+1;
      for (;i<=endPoint-1;i++){
        if (necklace.get(i)!=necklace.get(startPoint)&&necklace.get(i)!='w'){
          break;
        }
      }
      return i-1;
    } else {
      int i=startPoint-1;
      for (;i>=endPoint+1;i--){
        if (necklace.get(i)!=necklace.get(startPoint)&&necklace.get(i)!='w'){
          break;
        }
      }
      return i+1;
    }
  }

}

package Karl.Water;

import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.List;

public class beads1 {
  List<Integer> list = new ArrayList<Integer>();
  public int judge(String s){
    if(s.charAt(0)=='w'){
      return judgeE(s);
    }else{
      return judgeB(s);
    }
  }
  public int judgeE(String s){
    int result=0;
    int j=0;
    char c=s.charAt(s.length()-1);
    for(int k=s.length()-1;k>0;k--){
      j++;
      if(c!=s.charAt(k-1)&&s.charAt(k-1)!='w'){
        list.add(j);
        System.out.println(j);
        j=0;
        c=s.charAt(k-1);
      }
    }
    int h = 0;
    for(int k=0;k<s.length()-1;k++){
      if(s.charAt(k)==s.charAt(k+1)){
        h++;
      }
    }
  //  System.out.println(h+" "+s.length()/2);
    if(h==(s.length()-1)){
      list.add((s.length()/2));
    }
    list.add(0);
    int size = list.size();
    for(int p=0;p<size;p++){
      if(p==size-1){
        result = result>(list.get(p)+list.get(0))?result:(list.get(p)+list.get(0));
      }else{
        result = result>(list.get(p)+list.get(p+1))?result:(list.get(p)+list.get(p+1));
      }
    }
    return result;
  }
  public int judgeB(String s){
    int result=0,f=0;
    int j=0;
    char c=s.charAt(0);
    for(int k=0;k<s.length()-1;k++){
      j++;
      if(c!=s.charAt(k+1)&&s.charAt(k+1)!='w'){
        list.add(j);
        j=0;
        c=s.charAt(k+1);
      }
    }
    int h = 0;
    for(int k=0;k<s.length()-1;k++){
      if(s.charAt(k)==s.charAt(k+1)){
        h++;
      }
    }
  //  System.out.println(h+" "+s.length()/2);
    if(h==(s.length()-1)){
      list.add((s.length()/2));
    }
    list.add(0);
    int size = list.size();
    for(int p=0;p<size;p++){
      if(p==size-1){
        result = result>(list.get(p)+list.get(0))?result:(list.get(p)+list.get(0));
      }else{
        result = result>(list.get(p)+list.get(p+1))?result:(list.get(p)+list.get(p+1));
      }
    }
    return result;
  }
  public static void main(String[] args) throws IOException {
    beads1 b = new beads1();
    BufferedReader br = new BufferedReader(new FileReader("beads.in"));
    PrintWriter pw = new PrintWriter (new FileWriter("beads.out"));
    String s1 = br.readLine();
    String s2 = br.readLine();
    pw.println(b.judge(s2+s2));
    pw.close();
    br.close();
  }
}