清華複試-成績排序

題目描述

查找和排序

題目：輸入任意（用戶，成績）序列，能夠得到成績從高到低或從低到高的排列,相同成績
      都按先錄入排列在前的規則處理。

   例示：
   jack      70
   peter     96
   Tom       70
   smith     67

   從高到低  成績            
   peter     96    
   jack      70    
   Tom       70    
   smith     67    

   從低到高

   smith     67  

   Tom       70    
   jack      70    
   peter     96      

 

解題思路一：

Treemap

package com.tonyluis.oj;

import java.util.*;
import java.util.Map.*;

public class Main {

	public static void main(String[] args) {
		@SuppressWarnings("resource")
		Scanner in = new Scanner(System.in);
		TreeMap<Integer, List<String>> treeMap = new TreeMap<Integer, List<String>>();
		while (in.hasNext()) {
			int num = in.nextInt();
			int state = in.nextInt();
			for (int i = 0; i < num; i++) {
				String name = in.next();
				int score = in.nextInt();
				if (treeMap.containsKey(score))
					treeMap.get(score).add(name);
				else {
					List<String> list = new ArrayList<String>();
					list.add(name);
					treeMap.put(score, list);
				}
			}
			List<Entry<Integer, List<String>>> list = new ArrayList<Entry<Integer, List<String>>>(treeMap.entrySet());
			if (state == 0)
				Collections.reverse(list);
			for (Entry<Integer, List<String>> entry : list)
				for (String s : entry.getValue())
					System.out.println(s + " " + entry.getKey());
			treeMap.clear();
		}
	}
}

 思路二：

LinkedHashMap+Comparator

import java.util.*;
import java.util.Map.*;
public class Main {

	public static void main(String[] args) {
		@SuppressWarnings("resource")
		Scanner in = new Scanner(System.in);
		LinkedHashMap<Integer, List<String>> hm = new LinkedHashMap<Integer, List<String>>();
		while (in.hasNext()) {
			int num = in.nextInt();
			int state = in.nextInt();
			for (int i = 0; i < num; i++) {
				String name = in.next();
				int score = in.nextInt();
				if (hm.containsKey(score))
					hm.get(score).add(name);
				else {
					List<String> list = new ArrayList<String>();
					list.add(name);
					hm.put(score, list);
				}
			}
			List<Entry<Integer, List<String>>> list = new ArrayList<Entry<Integer, List<String>>>(hm.entrySet());

			Comparator<Entry<Integer, List<String>>> c1 = new Comparator<Entry<Integer, List<String>>>() {
				@Override
				public int compare(Entry<Integer, List<String>> arg0, Entry<Integer, List<String>> arg1) {
					// TODO Auto-generated method stub
					return arg0.getKey() - arg1.getKey();
				}
			};
			Comparator<Entry<Integer, List<String>>> c2 = new Comparator<Entry<Integer, List<String>>>() {
				@Override
				public int compare(Entry<Integer, List<String>> arg0, Entry<Integer, List<String>> arg1) {
					// TODO Auto-generated method stub
					return arg1.getKey() - arg0.getKey();
				}
			};
			if (state == 1)
				Collections.sort(list, c1);
			else
				Collections.sort(list, c2);
			for (Entry<Integer, List<String>> entry : list)
				for (String s : entry.getValue())
					System.out.println(s + " " + entry.getKey());
            hm.clear();
		}
	}
}