金山云Java方向9.16笔试
第一题：用long也越界了好像，n也太大了。过了91％。
public class Main {
public static void main(String[] args) {
Scanner in=new Scanner(System.in);
while (in.hasNext())
{
int n=in.nextInt();
if(n<0)
{
System.out.println(0);
continue;
}
long[] nums=new long[n];
long pre=0;
nums[0]=1;
for(int i=1;i<n;i++)
{
nums[i]=nums[i-1]+pre;
pre=nums[i-1];
}
for(int i=0;i<n;i++)
{
for(int j=0;j<=i;j++)
{
System.out.print(nums[j]+" ");
}
for(int k=i-1;k>=0;k--)
{
System.out.print(nums[k]+" ");
}
System.out.println();
}
}
}
} 第二题：反序列化二叉树+最近公共祖先。两道原题的结合版。AC public class Main {
static class TreeNode{
public int val;
public TreeNode left;
public TreeNode right;
public TreeNode(int val)
{
this.val=val;
}
}
static TreeNode p=new TreeNode(-1);
static TreeNode q=new TreeNode(-1);
static int pVal;
static int qVal;
public static void main(String[] args) {
Scanner in=new Scanner(System.in);
while (in.hasNextLine())
{
String id=in.nextLine();
if(id==null || id.equals(""))
{
System.out.println(-1);
continue;
}
String[] ids = id.split(" ");
LinkedList<Integer> queue=new LinkedList<>();
for(int i=0;i<ids.length;i++)
{
queue.offer(Integer.valueOf(ids[i]));
}
String virus=in.nextLine();
String[] viruses = virus.split(" ");
pVal=Integer.valueOf(viruses[0]);
qVal=Integer.valueOf(viruses[1]);
TreeNode root=bulidTree(queue);
TreeNode res=getRes(root);
if(res==null)
{
System.out.println(-1);
}else
{
System.out.println(res.val);
}
}
}
private static TreeNode getRes(TreeNode root) {
if(root==null || root==p || root==q) return root;
TreeNode left=getRes(root.left);
TreeNode right=getRes(root.right);
if(left==null) return right;
if(right==null) return left;
return root;
}
private static TreeNode bulidTree(LinkedList<Integer> queue) {
int val=queue.poll();
if(val==-1)
{
return null;
}
TreeNode root=new TreeNode(val);
if(pVal==root.val)
{
p=root;
}
if(qVal==root.val)
{
q=root;
}
root.left=bulidTree(queue);
root.right=bulidTree(queue);
return root;
}
}
