京东笔试4.16
求指点
第一题 为啥只通过36%
public class TestDemo {
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int count = sc.nextInt();
for(int i=0;i<count;i++){
int n = sc.nextInt();
sc.nextLine();
Deque<String> stack = new ArrayDeque<>();
boolean flag = true;
for(int j=0;j<n;j++){
String[] s = sc.nextLine().split(" ");
if(s.length==1){
stack.push(s[0]);
}else if(stack.size()==0 || !stack.pop().equals(s[1])){
flag = false;
break;
}
}
if(stack.size()==0 && flag){
System.out.println("Yes");
}else{
System.out.println("No");
}
}
}
}
第二题只通过18
public class TestDemo {
static List<Integer> list;
static int max;
public static void main(String[] args) {
Scanner sc = new Scanner(System.in);
int count = sc.nextInt();
for(int i=0;i<count;i++){
max = Integer.MIN_VALUE;
list = new ArrayList<>();
int n = sc.nextInt();
int[] nums = new int[n];
for(int j=0;j<n;j++){
nums[j] = sc.nextInt();
}
helper(nums,0,false);
System.out.println(max);
}
}
public static void helper(int[] nums,int pos,boolean flag){
if(pos==nums.length){
int val = list.get((list.size()-1)/2);
if(val==5){
System.out.println(list);
}
max = Math.max(val,max);
return;
}
// 如果flag为false，说明前一个使用了，可以跳过当前
if(!flag){
helper(nums,pos+1,true);
}
// 使用当前
list.add(nums[pos]);
helper(nums,pos+1,false);
list.remove(list.size()-1);
}
}
