哔哩哔哩后台笔试AC，
1.单词反转，采用栈，先进后出的特点：
package bilibili;
import java.util.Scanner;
import java.util.Stack;
public class Main {
public static void main(String[] args) {
Scanner scanner=new Scanner(System.in);
String str="";
while (scanner.hasNext()) {
str=scanner.nextLine();
String[] strings=str.split(" ");
Stack< String> stack=new Stack<>();
for (int i = 0; i < strings.length; i++) {
stack.push(strings[i]);
}
while (!stack.isEmpty()) {
System.out.print(stack.pop()+" ");
}
}
scanner.close();
}
} 3.背包问题，采用标记价值的索引号跟踪 package Maxbag;
import java.util.Arrays;
import java.util.Scanner;
public class Main {
public static void main(String[] args) {
Scanner scanner=new Scanner(System.in);
int N,M,sum=0,i;
while (scanner.hasNext()) {
N=scanner.nextInt();
M=scanner.nextInt();
int [] w=new int[N];
int [] v=new int[N];
double [] p=new double[N];
double [][] q=new double[N][N];
for ( i = 0; i < N; i++) {
w[i]=scanner.nextInt();
}
for ( i = 0; i < N; i++) {
v[i]=scanner.nextInt();
}
for (i = 0; i < N; i++) {
p[i]=v[i]/w[i];
q[i][i]=p[i];
}
Arrays.sort(p);
int num=N-1;
for ( i = 0; i < N; i++) {
if (q[i][i]==p[num]) {
M-=w[i];
if (M>0) {
sum+=v[i];
}
if (M<0) {
break;
}
num--;
}
}
System.out.println(sum);
}
scanner.close();
}
}
可能升个本会好点，现在学历歧视太严重了