A room with headlights on on a cloudy day
catalogue
The following statement is correct
The total number of handshakes generated by establishing and closing a tcp is
What are the similarities between TCP protocol and UDP protocol in computer networks
Given the port number bound to a process, the command to query the process is
The following protocols belong to the application layer:
Lee_921: add the least number of valid parentheses
Option 1
The following statement is correct
Threads in java are non preemptive
Threads in java cannot share data
Every java program has at least one thread, the main thread
Threads in java cannot share code
java multithreading is based on preemptive implementation Multithreading in java can use a shared memory area: heap method area A piece of code in java is either an instance method or a static method. The code itself is stored in the method area and belongs to the thread sharing area
The total number of handshakes generated by establishing and closing a tcp is
7
6
3
5
The number of handshakes refers to the number of network communications, that is, the number of network packets sent Establish three handshakes and four waves, a total of seven
What are the similarities between TCP protocol and UDP protocol in computer networks
Connectionless oriented protocol
Connection oriented protocol
The rest of the options are wrong
Transport layer protocol
Both tcp and udp are transport layer protocols. tcp is connected and udp is connectionless.
Given the port number bound to a process, the command to query the process is
ps
find
netstat
show
Known process name, query method: ps -ef |grep process name If the process port is known, the query method is netstat -anp|grep process name
The following protocols belong to the application layer:
TCP
IP
ARP
FTP
tcp is the transport layer ip is a network layer protocol arp is a protocol between data link layer and network layer
02 code
Lee_921: add the least number of valid parentheses
Given a string S composed of '(' and ')' parentheses, we need to add the least parentheses ('(' or ')' anywhere) to make the resulting parenthesis string valid.
Formally speaking, the parenthesized string is valid only if one of the following points is satisfied:
It is an empty string, or it can be written as AB (A connects with B), where A and B are valid strings, or it can be written as (A), where A is valid string. Given A parenthesis string, returns the minimum number of parentheses that must be added for the result string to be valid.
Source: LeetCode link: Force buckle The copyright belongs to Lingkou network. For commercial reprint, please contact the official authorization, and for non-commercial reprint, please indicate the source.
public int minAddToMakeValid(String s) {
if (s.length() == 0 || s == null) return 0;
int count = 0;
int res = 0;
for (int i = 0; i < s.length(); i++) {
if (s.charAt(i) == '('){
count++;
}else {
count--;
}
if (count < 0 ){
res++;
count = 0;
}
}
return res+=count;
}Lee_ 1492: factor k of n
//Use stack for violent resolution;
class Solution {
public int kthFactor(int n, int k) {
Stack<Integer> stack = new Stack<>();
for (int i = 1; i <= n ; i++) {
if (n %i == 0){
stack.push(i);
}
}
if (stack.size() < k) {
return -1;
}
int len = stack.size();
for (int i = 0; i < len-k ; i++) {
stack.pop();
}
return stack.peek();
}
}//optimization
public class Test1 {
public int KthFac(int n ,int k){
int count = 0 ,i;
for (i = 1; i*i<=n ; i++) {
if (n % i == 0){
count++;
if (count == k){
return i;
}// If the value of k has been changed before
}
}
i--;
if (i*i == n){
i--;
}
for (; i >0 ; i--) {
if (n% i == 0 ){
count++;
if (count == k){
return n/i;
}
}
}
return -1;
}
}