SRM DIV2 571 FoxAndMp3Easy

【题意】按照指定规则给mp3歌曲排序，输出前50个歌曲名。

【算法】：

1.建立歌名字符串(不包含“.mp3”)数组

2.排序

3.取出前50个，加上后缀名.mp3

【Java代码】来自菜鸟

 1 import java.util.*;
 2 import java.util.regex.*;
 3 import java.text.*;
 4 import java.math.*;
 5 
 6 
 7 public class FoxAndMp3Easy
 8 {
 9     public String[] playList(int n)
10     {
11         TreeSet<String> set = new TreeSet<String>();
12         int i;
13         
14         for(i=1;i<=n;i++){
15             set.add(""+i);
16         }
17         
18         String[] r = new String[Math.min(50,n)];
19         Iterator<String> it = set.iterator();
20         
21         for(i=0;i<Math.min(50, n);i++){
22             r[i]=it.next()+".mp3";
23         }
24         
25         return r;
26     }
27     
28 
29 }
30 //Powered by KawigiEdit 2.1.4 (beta) modified by pivanof!

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【Java代码】来自大神

import java.util.*; 
public class FoxAndMp3Easy { 
  public String[] playList(int n) { 
    List<String> mp3List = new ArrayList<String>(); 
    for(int i=1;i<=n;i++) { 
      mp3List.add(String.valueOf(i)); 
    } 
    Collections.sort(mp3List, new Comparator<String>() {  
        public int compare(String a, String b) {  
         return a.compareTo(b);  
         }  
        }); 
        int len = mp3List.size(); 
        if(len>50) 
          len = 50; 
        String[] result = new String[len]; 
        for(int i=0;i<len;i++) { 
          result[i] = mp3List.get(i)+".mp3"; 
        } 
        return result; 
  } 
}

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【C++代码】来自大神

【分析】大神直接把".mp3"加进去比较，因为'.'是比'0'到'9'都小，'.'是46，'0'是48。

#include <vector>
#include <list>
#include <map>
#include <set>
#include <queue>
#include <deque>
#include <stack>
#include <bitset>
#include <algorithm>
#include <functional>
#include <numeric>
#include <utility>
#include <sstream>
#include <iostream>
#include <iomanip>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <ctime>
#include <cstring>
#include <climits>
 
using namespace std;
#define INF INT_MAX
#define EPS 1e-
#define abs(a) ((a)<0?-(a):(a))
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define REP(i,n) FOR(i,0,n)
#define MP make_pair
#define FR first
#define SE second
#define PB(X) push_back(X)
#define tri(a,b,c) MP(a,MP(b,c))
#define IND(arr,ind) (lower_bound(all(arr),ind)-arr.begin())
 
class FoxAndMp3Easy {
public:
  vector <string> playList(int n) {
    vector <string> ret;
    for(int i=1;i<=n;i++){
      stringstream ss;
      ss<<i;
      ret.push_back(ss.str()+".mp3");
    }
    sort(ret.begin(),ret.end());
    if(ret.size()>50){
      ret.erase(ret.begin()+50,ret.end());
    }
    return ret;
  }
};
 
 
 
//Powered by KawigiEdit 2.1.8 (beta) modified by pivanof!

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【总结】：题还是比较简单的。

附上ASCII码表http://www.96yx.com/tool/ASC2.htm