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();
}
}
}
原文：http://www.cnblogs.com/tonyluis/p/5835563.html