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/*
* TestList.java
* Version 1.0.0
* Created on 2017年12月15日
* Copyright ReYo.Cn
*/
package reyo.sdk.utils.test.list2;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class TestList {
public static void main(String[] args) {
List<String> list1 = new ArrayList<String>();
List<String> list2 = new ArrayList<String>();
for (int i = 0; i < 10000; i++) {
list1.add("test" + i);
list2.add("test" + i * 2);
}
getDiffrent(list1, list2);
getDiffrent3(list1, list2);
getDiffrent5(list1, list2);
getDiffrent4(list1, list2);
getDiffrent2(list1, list2);
// getDiffrent3 total times 32271699
// getDiffrent5 total times 12239545
// getDiffrent4 total times 16786491
// getDiffrent2 total times 2438731459
}
/**
* 获取两个List的不同元素
* @param list1
* @param list2
* @return
*/
private static List<String> getDiffrent5(List<String> list1, List<String> list2) {
long st = System.nanoTime();
List<String> diff = new ArrayList<String>();
List<String> maxList = list1;
List<String> minList = list2;
if (list2.size() > list1.size()) {
maxList = list2;
minList = list1;
}
Map<String, Integer> map = new HashMap<String, Integer>(maxList.size());
for (String string : maxList) {
map.put(string, 1);
}
for (String string : minList) {
if (map.get(string) != null) {
map.put(string, 2);
continue;
}
diff.add(string);
}
for (Map.Entry<String, Integer> entry : map.entrySet()) {
if (entry.getValue() == 1) {
diff.add(entry.getKey());
}
}
System.out.println("getDiffrent5 total times " + (System.nanoTime() - st));
return diff;
}
/**
* 获取两个List的不同元素
* @param list1
* @param list2
* @return
*/
private static List<String> getDiffrent4(List<String> list1, List<String> list2) {
long st = System.nanoTime();
Map<String, Integer> map = new HashMap<String, Integer>(list1.size() + list2.size());
List<String> diff = new ArrayList<String>();
List<String> maxList = list1;
List<String> minList = list2;
if (list2.size() > list1.size()) {
maxList = list2;
minList = list1;
}
for (String string : maxList) {
map.put(string, 1);
}
for (String string : minList) {
Integer cc = map.get(string);
if (cc != null) {
map.put(string, ++cc);
continue;
}
map.put(string, 1);
}
for (Map.Entry<String, Integer> entry : map.entrySet()) {
if (entry.getValue() == 1) {
diff.add(entry.getKey());
}
}
System.out.println("getDiffrent4 total times " + (System.nanoTime() - st));
return diff;
}
/**
* 获取两个List的不同元素
* @param list1
* @param list2
* @return
*/
private static List<String> getDiffrent3(List<String> list1, List<String> list2) {
long st = System.nanoTime();
Map<String, Integer> map = new HashMap<String, Integer>(list1.size() + list2.size());
List<String> diff = new ArrayList<String>();
for (String string : list1) {
map.put(string, 1);
}
for (String string : list2) {
Integer cc = map.get(string);
if (cc != null) {
map.put(string, ++cc);
continue;
}
map.put(string, 1);
}
for (Map.Entry<String, Integer> entry : map.entrySet()) {
if (entry.getValue() == 1) {
diff.add(entry.getKey());
}
}
System.out.println("getDiffrent3 total times " + (System.nanoTime() - st));
return diff;
}
/**
* 获取连个List的不同元素
* @param list1
* @param list2
* @return
*/
private static List<String> getDiffrent2(List<String> list1, List<String> list2) {
long st = System.nanoTime();
list1.retainAll(list2);
System.out.println("getDiffrent2 total times " + (System.nanoTime() - st));
return list1;
}
/**
* 获取两个List的不同元素
* @param list1
* @param list2
* @return
*/
private static List<String> getDiffrent(List<String> list1, List<String> list2) {
long st = System.nanoTime();
List<String> diff = new ArrayList<String>();
for (String str : list1) {
if (!list2.contains(str)) {
diff.add(str);
}
}
System.out.println("getDiffrent total times " + (System.nanoTime() - st));
return diff;
}
}
|
getDiffrent total times 320118400
getDiffrent3 total times 12051500
getDiffrent5 total times 6301100
getDiffrent4 total times 7527300
getDiffrent2 total times 298880900