PAT乙级答案（JAVA）

import java.io.*; import java.util.*; public class Main { static PrintWriter out = new PrintWriter(new BufferedOutputStream(System.out)); static BufferedReader ins = new BufferedReader(new InputStreamReader(System.in)); static StreamTokenizer in = new StreamTokenizer(ins); public static void main(String[] args) throws IOException { in.ordinaryChars('0', '9'); in.wordChars('0', '9'); in.nextToken(); int N=Integer.parseInt(in.sval); in.nextToken(); int M=Integer.parseInt(in.sval); char[][] ids=new char[N][]; int[] s=new int[N]; for (int i=0;i<N;i++){ in.nextToken(); ids[i]=in.sval.toCharArray(); in.nextToken(); s[i]=Integer.parseInt(in.sval); } List<Student> list=new ArrayList<>(); for (int i=0;i<M;i++){ list.clear(); boolean f=true; in.nextToken(); int K=Integer.parseInt(in.sval); in.nextToken(); String cs=in.sval; char[] c=cs.toCharArray(); out.printf("Case %d: %d %s\n",(i+1),K,cs); switch (K){ case 1: for (int j=0;j<N;j++){ if(ids[j][0]==c[0]){ list.add(new Student(ids[j],s[j])); f=false; } } if(!f)Collections.sort(list,(o1, o2) -> o1.s!=o2.s?o2.s-o1.s:(String.valueOf(o1.id).compareTo(String.valueOf(o2.id)))); if(!f)list.forEach(o-> out.println(o)); break; case 2: int sn=0,ss=0; for(int j=0;j<N;j++){ if(cmp(ids[j],c,1,3)){ sn++; ss+=s[j]; f=false; } } if(!f)out.println(sn+" "+ss); break; case 3: for (int j=0;j<N;j++){ if(cmp(ids[j],c,4,6)){ f=false; char[] cc=new char[3]; System.arraycopy(ids[j],1,cc,0,3); int index=-1; for (int z=0;z<list.size();z++){ if(cmp(list.get(z).id,cc,0,3)) index=z; } if(index==-1){ list.add(new Student(cc,1)); }else{ list.get(index).s++; } } } if(!f)Collections.sort(list,(o1, o2) -> o1.s!=o2.s?o2.s-o1.s:(String.valueOf(o1.id).compareTo(String.valueOf(o2.id)))); if(!f)list.forEach(o->out.println(o)); break; } if (f) out.println("NA"); } out.close(); } public static boolean cmp(char[] a,char[] b,int start,int end){ for (int i=start,len=start+end,j=0;i<len;i++,j++) if(a[i]!=b[j]) return false; return true; } } class Student{ char[] id; int s; public Student(char[] id,int s){ this.id=id; this.s=s; } @Override public String toString() { final StringBuilder sb = new StringBuilder(); sb.append(id).append(" ").append(s); return sb.toString(); } }