import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
public class Main {
static int findMissingNumber(int start, int end, List<Integer> list) {
for (int i = start; i <= end; i++) {
if (!list.contains(i)) {
return i;
}
}
return -1;
}
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shuffle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);
System.out.println("missing number: " + found);
System.out.println(removed == found ? "测试成功" : "测试失败");
}
}
韦雪松