清华复试-成绩排序

题目描述

查找和排序

题目：输入任意（用户，成绩）序列，可以获得成绩从高到低或从低到高的排列,相同成绩
都按先录入排列在前的规则处理。

   例示：
   jack      70
   peter     96
   Tom       70
   smith     67

   从高到低  成绩
   peter     96
   jack      70
   Tom       70
   smith     67

从低到高

smith 67

   Tom       70
   jack      70
   peter     96

解题思路一：

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();
		}
	}
}

清华复试-成绩排序

题目描述

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