兴业数金笔试
选择题：存储过程、异常捕获、交换机的功能、序列化、线程优先级、SpringMVC、yield、数组等
代码题：分解质因子。
由于之前在做笔试时遇到了求素数的题，所以就回忆了下线性素数筛，这次笔试就用到了。
题干描述不充分的地方是，没有给待分解整数的范围。
import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int num = sc.nextInt();
StringBuilder cache = new StringBuilder();
cache.append(num).append("=");
if (num < 4) {
cache.append(num);
} else {
List<Integer> primeList = getPrime(num);
int i = 0;
while (num % primeList.get(i) != 0) {
++i;
}
cache.append(primeList.get(i));
num = num / primeList.get(i);
while(num != 1) {
while (num % primeList.get(i) != 0) {
++i;
}
cache.append("*").append(primeList.get(i));
num /= primeList.get(i);
}
}
System.out.println(cache);
}
static List<Integer> getPrime(int num) {
int m = (int)Math.sqrt(num + 0.5);
boolean[] vis = new boolean[num + 1];
for (int i = 2; i <= m; ++i) {
if (!vis[i]) {
for (int j = i * i; j <= num; j += i) {
vis[j] = true;
}
}
}
List<Integer> ret = new ArrayList<>();
for (int i = 2; i <= num; ++i) {
if (!vis[i]) {
ret.add(i);
}
}
return ret;
}
}
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