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Difference between Set and MultiSet in C++

Nitin Sharma
Nitin Sharma
Updated on 09-Jun-2020 5K+ Views

In C++, both Set and MultiSet are the type of data structures which are used to store the data for easy accessing and insertion. On the basis of characteristics of both these data structures we can distinguish between Set and MultiSet.Following are the important differences between Set and MultiSet −Sr. No.KeySetMultiSet1DefinitionSet in C++ can be defined as a type of associative container which stores the data in key value pair and in which each value element has to be unique, because the value of the element identifies it.On other hand MultiSet are part of the C++ STL (Standard Template Library) ...

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Number of Paths with Max Score in C++

Arnab Chakraborty
Arnab Chakraborty
Updated on 08-Jun-2020 261 Views

Suppose we have a square board of characters. We can move on the board starting at the bottom right square marked with the character 'S'. Now we need to reach the top left square marked with the character 'E'. The other squares are labeled either with a numeric character from 1 to 9 or with an obstacle 'X'. In one move we can go up, left or up-left only when there is no obstacle there.We have to find the list of two numbers: the first number is the maximum sum of the numeric characters we can collect, and the second ...

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Binary Tree Cameras in C++

Arnab Chakraborty
Arnab Chakraborty
Updated on 08-Jun-2020 322 Views

Suppose we have a binary tree; we place cameras on the nodes of the tree. Now each camera at a node can monitor its parent, itself, and its children. We have to find the minimum number of cameras needed to monitor all nodes of the tree.So, if the input is like −then the output will be 1, because only one camera is enough to track all.To solve this, we will follow these steps −Define one set called covered, of type TreeNode (Tree node has left, right and data field)Define a function solve(), this will take node, parent, if node is ...

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Stream of Characters in C++

Arnab Chakraborty
Arnab Chakraborty
Updated on 04-Jun-2020 682 Views

Suppose we want to implement the StreamChecker class as follows −StreamChecker(words) − This is the constructor, this initializes the data structure with the given words.query(letter) − This returns true when for some k >= 1, the last k characters queried (in order from oldest to newest, including this letter just queried) spell one of the words in the given list.So, if the input is like word list = ["ce", "g", "lm"], then call query many times for [a, b, c, e, f, g, h, i, j, k, l, m], then the output will be true for e, g, m, and ...

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Styling html pages in Node.js

Shyam Hande
Shyam Hande
Updated on 13-May-2020 7K+ Views

In html files we can simply add style in head section −                    //add css code           We can add inline css styles as well in html directly.Generally css is separated from the html code. Third option add css is to include a css file .How to serve static files in Node.js?Generally css files are added with below tag −     Express js provides a middleware to seve static file. This middleware gives read access to given folder.app.use(express.static(path.join(__dirname, ‘public’)));path: its our core module ...

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Serving html pages from node.js

Shyam Hande
Shyam Hande
Updated on 13-May-2020 2K+ Views

So far we sent html code directly from the send(0 function in response object. For sending larger code, we definitely require to have a separate file for html code.sendFile() function−Response object gives a sendFile() function to return a html file to client.How to provide path to html file in sendFile() ?We import the path core module of node.js.const path = require(‘path’);path has a join function . __dirname is a global variable which holds the actual path to project main folder.path.join(__dirname, ‘views’, ‘add-user.html’); This will refer to the actual file location of add-user html code.App.jsconst http = require('http'); const express = ...

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Filtering paths and creating html page in express.js

Shyam Hande
Shyam Hande
Updated on 13-May-2020 472 Views

We added express router to handle routes. One single router file handles multiple routes.Adding a path for router in App.js −const http = require('http'); const express = require('express'); const bodyParser = require('body-parser'); const route = require('./routes'); const app = express(); app.use(bodyParser.urlencoded({extended: false})); app.use('/test', route); app.use((req, res, next)=>{    res.status(404).send(' Page not found '); }); const server = http.createServer(app); server.listen(3000);In router middleware we used path −/p>app.use('/test', route);Router will handle all paths starting with /test e.g. /test/add-usernameWe have to change action in form in routes.js file −router.get('/add-username', (req, res, next)=>{    res.send('     Send '); });Routes.js file −const express ...

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Adding 404 page in express

Shyam Hande
Shyam Hande
Updated on 13-May-2020 1K+ Views

Now we have a App.js and route.js for handling routes. For any other http requests for which we have not added any request handling will results into an error page. Example for url ‘test’ −App.jsconst http = require('http'); const express = require('express'); const bodyParser = require('body-parser'); const route = require('./routes'); const app = express(); app.use(bodyParser.urlencoded({extended: false})); app.use(route); const server = http.createServer(app); server.listen(3000);Showing meaningful error message on incorrect url’s−We can add a all catch middleware for incorrect url at the end of all middleware’s in App.js −const http = require('http'); const express = require('express'); const ...

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How to use express router

Shyam Hande
Shyam Hande
Updated on 13-May-2020 2K+ Views

In earlier examples, we wrote all routing code in a single file App.js. But in real world scenarios, we have to split the code into multiple files.We can create separate files and import them but express gives a router mechanism which is easy to use.Create a separate file called route.js (name can be anything)Create router using express −const express = require('express'); const router = express.Router();exporting router −module.exports = router;Adding routing functions −router.get('/add-username', (req, res, next)=>{    res.send(' Send '); });  router.post('/post-username', (req, res, next)=>{    console.log('data: ', req.body.username);    res.redirect('/'); });Similar to functions we used in App.js ...

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Parsing incoming requests in express.js

Shyam Hande
Shyam Hande
Updated on 13-May-2020 1K+ Views

To receive some data in http request , lets add a form on url path ‘/add-username’:app.use('/add-username', (req, res, next)=>{    res.send(' Send '); });For parsing the http request, we requires a third party library body-parser: It’s a production required dependencynpm install –save body-parserexpress js provides middleware use function to include a body parser before adding middleware.const http = require('http'); const express = require('express'); const bodyParser = require('body-parser'); const app = express(); app.use(bodyParser.urlencoded({extended: false}));the use(0 function shown above uses next() function by default so http request gets passed to next middleware without any trouble.The above ...

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