POJ 1002 487-3279

题目链接：http://poj.org/problem?id=1002

题目大意：给一系列的含数字和字母的字符串，其中一些字母对应了一个数字，最终可以将原来的字符串转换成一串数字（电话号码），求出每组号码出现的次数

开始时，做得比较复杂，用了两个 ArrayList,花了很多时间！TLE！后来，使用了 HashMap 得到了优化，终于AC!

 

/**
* @Author：胡家威
* @CreateTime：2011-4-21 下午08:52:57
* @Description：AC
*/

package ACM.POJ;

import java.util.Arrays;
import java.util.HashMap;
import java.util.Scanner;
import java.util.Set;

public class POJ1002 {

public static void main (String[] args) {
Scanner scanner = new Scanner(System.in);
HashMap hs = new HashMap();
int line = scanner.nextInt();
boolean nodup = true;
for (int i=0; i<line; i++){
char[] chars = new char[8];
chars[3] = '-';
int k = 0;
String src = scanner.next();
for (int j = 0; j < src.length(); j++){
char c = src.charAt(j);
if(c == '-'){
continue;
}else if(Character.isLetter(c)){
if(c=='A' || c=='B' || c=='C'){
c = '2';
}else if(c=='D' || c=='E' || c=='F'){
c = '3';
}else if(c=='G' || c=='H' || c=='I'){
c = '4';
}else if(c=='J' || c=='K' || c=='L'){
c = '5';
}else if(c=='M' || c=='N' || c=='O'){
c = '6';
}else if(c=='P' || c=='R' || c=='S'){
c = '7';
}else if(c=='T' || c=='U' || c=='V'){
c = '8';
}else if(c=='W' || c=='X' || c=='Y'){
c = '9';
}
if(k == 3){
chars[++k] = c;
k++;
}else{
chars[k] = c;
k++;
}
}else if(Character.isDigit(c)){
if(k == 3){
chars[++k] = c;
k++;
}else{
chars[k] = c;
k++;
}
}
}
String phone = String.valueOf(chars);
if(hs.containsKey(phone)){
nodup = false;
hs.put(phone,(Integer)hs.get(phone)+1);
}else{
hs.put(phone,1);
}
}

if(nodup){
System.out.println ("No duplicates.");
}else{
Set<String> phones = hs.keySet();  //这里 String 很重要！
String[] str = phones.toArray(new String[phones.size()]);
Arrays.sort(str);
for(String s : str){
int value = (Integer)hs.get(s);
if(value > 1){
System.out.println (s+" "+value);
}
}
}
}
}

.csharpcode, .csharpcode pre
{
font-size: small;
color: black;
font-family: consolas, "Courier New", courier, monospace;
background-color: #ffffff;
/*white-space: pre;*/
}
.csharpcode pre { margin: 0em; }
.csharpcode .rem { color: #008000; }
.csharpcode .kwrd { color: #0000ff; }
.csharpcode .str { color: #006080; }
.csharpcode .op { color: #0000c0; }
.csharpcode .preproc { color: #cc6633; }
.csharpcode .asp { background-color: #ffff00; }
.csharpcode .html { color: #800000; }
.csharpcode .attr { color: #ff0000; }
.csharpcode .alt
{
background-color: #f4f4f4;
width: 100%;
margin: 0em;
}
.csharpcode .lnum { color: #606060; }