algorithm - Nested loop execution -


this simple question, reason i'm getting confused , it's annoying. 

def test(): lo1 hi1:     j lo2 hi2:     body()

how many times body() execute for: lo1=1, hi1=n, lo2=i-2, hi2=i+2

the answer 5n times, have no idea how it!

i think easiest way understand run it.

for example n=10, following java code prints values of i , j in each iteration :

 (int i=0; i<=10; i++){      (int j=i-2; j<=i+2; j++)          system.out.println("i = " + + ", j= " + j);  }

the result follows:

i = 0, j= -2 = 0, j= -1 = 0, j= 0 = 0, j= 1 = 0, j= 2 = 1, j= -1 = 1, j= 0 = 1, j= 1 = 1, j= 2 = 1, j= 3 = 2, j= 0 = 2, j= 1 = 2, j= 2 = 2, j= 3 = 2, j= 4 = 3, j= 1 = 3, j= 2 = 3, j= 3 = 3, j= 4 = 3, j= 5 = 4, j= 2 = 4, j= 3 = 4, j= 4 = 4, j= 5 = 4, j= 6 = 5, j= 3 = 5, j= 4 = 5, j= 5 = 5, j= 6 = 5, j= 7 = 6, j= 4 = 6, j= 5 = 6, j= 6 = 6, j= 7 = 6, j= 8 = 7, j= 5 = 7, j= 6 = 7, j= 7 = 7, j= 8 = 7, j= 9 = 8, j= 6 = 8, j= 7 = 8, j= 8 = 8, j= 9 = 8, j= 10 = 9, j= 7 = 9, j= 8 = 9, j= 9 = 9, j= 10 = 9, j= 11 = 10, j= 8 = 10, j= 9 = 10, j= 10 = 10, j= 11 = 10, j= 12

you can see there 10 iterations i, , each i have 5 iterations of j(from i-2 i+2). hence 50 (5*n) iterations in total.


Comments

Post a Comment

Popular posts from this blog

node.js - Using Node without global install -

i'm working on few node & electron (atom shell) projects , i'm curious how them work without user having install node globally. i've seen few applications including node directory in project contains node.exe binary. how go setting node project use binary? edit: thought should add, i've searched everywhere answer this, unrelated results.
Read more

How to access a php class file from PHPFox framework into javascript code written in simple HTML file? -

i've website developed using phpfox v3.0.7 . now i'm trying implement 'sse(server sent events)' 1 of php files. reference i'm giving below necessary code part of file. file titled process.class.php , present @ location /var/www/module/notification/include/service/process.class.php present on server having ip http://34.124.40.142/ . <?php /** * [phpfox_header] */ header('content-type: text/event-stream'); header('cache-control: no-cache'); defined('phpfox') or exit('no dice!'); /** * * * @copyright [phpfox_copyright] * @author raymond benc * @package phpfox_service * @version $id: service.class.php 67 2009-01-20 11:32:45z raymond_benc $ */ class notification_service_process extends phpfox_service { /** * class constructor */ public function __construct() { $this->_stable = phpfox::gett('notification'); } public function add($...
Read more

java - Null response to php query in android, even though php works properly -

Image
table i'm trying retrieve above data using 2 php files below. want pass email parameter , return bets user = email. work fine when tested advanced rest client, problem not php. however, when try through android 2 java classes below, null pointer exception (logcat below) , json object returned null. i'm not sure error is, think i'm not passing parameter php , that's why it's producing null response. logcat 05-31 15:10:50.227 26074-26074/com.example.albert.betterapp e/androidruntime﹕ fatal exception: main process: com.example.albert.betterapp, pid: 26074 java.lang.runtimeexception: unable start activity componentinfo{com.example.albert.betterapp/com.example.albert.betterapp.displayallbets}: java.lang.nullpointerexception @ android.app.activitythread.performlaunchactivity(activitythread.java:2292) @ android.app.activitythread.handlelaunchactivity(activitythread.java:2350) @ android.app.activitythread.acce...
Read more