public class Main {
public static void main(String[] args) {
// 构造从start到end的序列:
final int start = 10;
final int end = 20;
List<Integer> list = new ArrayList<>();
for (int i = start; i <= end; i++) {
list.add(i);
}
// 洗牌算法suffle可以随机交换List中的元素位置:
Collections.shuffle(list);
// 随机删除List中的一个元素:
int removed = list.remove((int) (Math.random() * list.size()));
int found = findMissingNumber(start, end, list);
System.out.println(list.toString());
System.out.println("missing number: " + found);
System.out.println(removed == found ? "测试成功" : "测试失败");
/**
* TODO: 找出从start到end的缺失的数字并返回
*/
static int findMissingNumber(int start, int end, List<Integer> list) {
** //create a new ArrayList list2 which is the same as the initial list**
List<Integer> list2 = new ArrayList<>();
list2.add(i);
** //remove the elements of list from list2**
for (Integer n: list)
list2.remove(n);
//the last remain element in list2 is missing from list
if (list2.size()==1)
return list2.get(0);
else
return 0;
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Xtraordinary_Yuan
public class Main {
public static void main(String[] args) {
// 构造从start到end的序列:
final int start = 10;
final int end = 20;
List<Integer> list = new ArrayList<>();
for (int i = start; i <= end; i++) {
list.add(i);
}
// 洗牌算法suffle可以随机交换List中的元素位置:
Collections.shuffle(list);
// 随机删除List中的一个元素:
int removed = list.remove((int) (Math.random() * list.size()));
int found = findMissingNumber(start, end, list);
System.out.println(list.toString());
System.out.println("missing number: " + found);
System.out.println(removed == found ? "测试成功" : "测试失败");
}
/**
* TODO: 找出从start到end的缺失的数字并返回
*/
static int findMissingNumber(int start, int end, List<Integer> list) {
** //create a new ArrayList list2 which is the same as the initial list**
List<Integer> list2 = new ArrayList<>();
for (int i = start; i <= end; i++) {
list2.add(i);
}
** //remove the elements of list from list2**
for (Integer n: list)
list2.remove(n);
//the last remain element in list2 is missing from list
if (list2.size()==1)
return list2.get(0);
else
return 0;
}