京东2019校招算法工程师笔试题

CREATE TABLE `user` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT COMMENT '主键Id',
  `name` varchar(255) DEFAULT NULL COMMENT '名称',
  `age` int(11) DEFAULT NULL COMMENT '年龄',
  `address` varchar(255) DEFAULT NULL COMMENT '地址',
  `created_time` datetime DEFAULT NULL COMMENT '创建时间',
  `updated_time` datetime DEFAULT NULL COMMENT '更新时间',
  PRIMARY KEY (`id`),
  KEY `idx_com1` (`name`,`age`,`address`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='用户表'

union X{
    int x
    char y[4] 
}

#include <iostream>
using namespace std
class D{
    int d
public: 
    D(int x=1):d(x){}
    ~D(){cout<<"D"}} 
int main(){ 
    D d[]={_____________}
    D* p=new D[2]
    delete[]p
    return 0 
}

#include <iostream>
using namespace std
_______________________
void One(float one)
{
    cout<<"1"<<endl
}
void Two(float two)
{
    cout<<"2"<<endl
}
void Three(float three)
{
    cout<<"3"<<endl
}
int main()
{
    float i=1,j=2,k=3
    function = One
    function(i)
    function= Two
    function(j)
    function = Three
    function(k)
}

#include<iostream> 
using namespace std
class complex 
{ public:
int real
int imag
complex(int r=0,int i=0) 
{ real=r
imag=i}
_________________________________
}
complex add(complex &a,complex & b) 
{int r=a.real+b.real
int i=a.imag+b.imag
return complex(r,i)}  
int  main( ) 
{complex x(1,2),y(3,4),z
z=add(x,y)
cout<<z.real<<"+"<<z.imag<<"i"<<endl}  

#include <iostream> 
using namespace std 
template <class T>
void S(T &x, T &y)
{ T temp
   temp = x
   x = y
   y = temp}
template <class T>
void SS(T A[], int n)
{ int min    
  int i, j
  for (i=0 i<n-1 i++) 
  { min=i    
    for (j=_____ j<n j++) 
     if (A[j]<A[min]) min=j
    S(A[i], A[min])
  }   }

int main()   
{
    char c, s[20]
    strcpy(s, "Hello,World")
    printf("s[]=%6.9s\n", s)
    return 0
}

struct Student{
    int num
    char name[7]   
    short age
    char sex
}student1
int sz = sizeof(student1)

int main() {
 vector<int> vInt(1)
 cout << vInt[1]
 cout << vInt.at(1)
 return 0
}

int main() {
 vector<int> vInt
 for (int i=0 i<5 ++i)
 {
  vInt.push_back(i)
  cout << vInt.capacity() << " "
 }
 vector<int> vTmp(vInt)
 cout << vTmp.capacity() << "\n"
 return 0
}

int main() {
 int a(1), b(3), c(2)
 
 while (a < b < c)
 {
  ++a
  --b
  --c
 }
 cout << a << " " << b << " " << c << "\n"
 return 0
}

public class Main {
    public static void main(String[] args) {
        System.out.println("A")
        new Main()
        new Main()
    }
    public Main() {
        System.out.println("B")
    }
    {
        System.out.println("C")
    }
    static {
        System.out.println("D")
    }
}

public class Main {
    private static int x = 10
    private static Integer y = 10
    public static void updateX(int value) {
        value = 3 * value
    }
    public static void updateY(Integer value) {
        value = 3 * value
    }
    public static void main(String[] args) {
        updateX(x)
        updateY(y)
    }
}

public class Main {
    public static void main(String[] args) {
        String s1 = "abc"
        String s2 = "abc"
        System.out.println(s1 == s2)
        String s3 = new String("abc")
        System.out.println(s1 == s3)
    }
}

public class Test {
    public static void main(String[] args) {
        System.out.println(Test2.a)
    }
}
class Test2{
    public static final String a="JD"
    static {
        System.out.print("OK")
    }
}

public class Test {
    public static void main(String[] args) {
        System.out.println(Test2.a)
    }
}
class Test2{
    public static final String a=new String("JD")
    static {
        System.out.print("OK")
    }
}

public class Test {
    public static void main(String[] args) {
        System.out.println(Test2.a)
    }
}
class Test2{
    static {
        System.out.print("OK")
    }
    public static final String a=new String("JD")
}

public class Test {
    public static void main(String[] args) {
        System.out.print(B.c)
    }
}
class A {
    static {
        System.out.print("A")
    }
}
class B extends A{
    static {
        System.out.print("B")
    }
    public final static String c = "C"
}

public class Test {
    public static void main(String[] args) {
        System.out.print(B.c)
    }
}
class A {
    public static String c = "C"
    static {
        System.out.print("A")
    }
}
class B extends A{
    static {
        System.out.print("B")
    }
}

public class Test {
    public static void main(String[] args) throws Exception{
      ClassLoader classLoader=ClassLoader.getSystemClassLoader()
      Class clazz=classLoader.loadClass("A")
      System.out.print("Test")
      clazz.forName("A")
    }
}
class A{
    static {
        System.out.print("A")
    }
}

public class Main {
    public static void main(String[] args) {
        System.out.print(fun1())
    }
    public static String fun1() {
        try {
            System.out.print("A")
            return fun2()
        } finally {
            System.out.print("B")
        }
    }
    public static String fun2() {
        System.out.print("C")
        return "D"
    }
}

import java.util.ArrayList
import java.util.List
public class Main {
    public static void main(String[] args) {
        List<String> list = new ArrayList<>()
        for(int i=0i<100i++){
            list.add("a")
        }
    }
}

import java.util.concurrent.ArrayBlockingQueue
import java.util.concurrent.ThreadPoolExecutor
import java.util.concurrent.TimeUnit
public class Main {
    public static void main(String[] args) {
        ThreadPoolExecutor executor = new ThreadPoolExecutor(5, 10, 15, TimeUnit.SECONDS,
                new ArrayBlockingQueue<Runnable>(5), new ThreadPoolExecutor.CallerRunsPolicy())
    }
}

public class Main{
    public static ArrayList<String> list = new ArrayList<>()
    public static void main(String[] args) throws Exception{
        Thread t1 = new Main().new MyThread()
        Thread E10:E64t2 = new Thread(new Main().new MyRunnable())
        t1.setPriority(3)
        t2.setPriority(8)
        t1.start()
        t2.start()
        t2.join()
        for (int i = 0 i < 100000 i++) {
            i++
        }
        list.add("main")
        
        t1.join()
        for (String s : list) {
            System.out.println(s)
        }
    }
    class MyThread extends Thread{
        @Override
        public void run(){
            for (int i = 0 i < 100000 i++) {
                i++
            }
            list.add("Thread 1")
        }
    }
    class MyRunnable implements Runnable{
        @Override
        public void run(){
            for (int i = 0 i < 100000 i++) {
                Thread.yield()
                i++
            }
            list.add("Thread 2")
        }
    }
}

import re
m = re.search('[0-9]','a1b2c3d4')
print(m.group(0))

import datetime
t1 = datetime.datetime(2017,10,10,21,40)
t2 = datetime.datetime(2017,10,8,23,40)
tt1 = datetime.timedelta(seconds = 1200)
tt2 = datetime.timedelta(weeks = 3)
print(t1 - t2)

x = 5
x = square(x)
x = x + 1

def make_withdraw(balance):
        def withdraw(amount):
            nonlocal balance
            if amount > balance:
                print('Insufficient funds')
            else:
                balance = balance - amount
                print(balance)
        return withdraw