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Rabin-Karp algorithm in java #360

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262 changes: 131 additions & 131 deletions app.js
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,132 +1,132 @@
const express = require('express');
const mongoose = require('mongoose');
const bcrypt = require('bcrypt');
const cors = require('cors');
// Import required modules
// Create an Express app
const app = express();
// Enable CORS
app.use(express.json());
app.use(cors());
// Connect to MongoDB
mongoose.connect('mongodb://localhost:27017/cafe', { useNewUrlParser: true, useUnifiedTopology: true })
.then(() => {
console.log('Connected to MongoDB');
})
.catch((error) => {
console.error('Error connecting to MongoDB:', error);
});
// Define a user schema
const userSchema = new mongoose.Schema({
username: { type: String, required: true },
password: { type: String, required: true }
});
// Define a user model
const User = mongoose.model('User', userSchema);
const productSchema = new mongoose.Schema({
name: { type: String, required: true },
price: { type: Number, required: true },
quantity: { type: Number, required: true }
});
const Product = mongoose.model('Product', productSchema);
// Register a new user
app.post('/register', async (req, res) => {
try {
const { username, password } = req.body;
// Check if the username already exists
const existingUser = await User.findOne({ username });
if (existingUser) {
return res.status(400).json({ message: 'Username already exists' });
}
// Hash the password
const hashedPassword = await bcrypt.hash(password, 10);
// Create a new user
const newUser = new User({ username, password: hashedPassword });
await newUser.save();
res.status(201).json({ message: 'User registered successfully' });
} catch (error) {
console.error('Error registering user:', error);
res.status(500).json({ message: 'Internal server error' });
}
});
// User login
app.post('/login', async (req, res) => {
try {
const { username, password } = req.body;
// Find the user by username
const user = await User.findOne({ username });
if (!user) {
return res.status(404).json({ message: 'User not found' });
}
// Compare the password
const isPasswordValid = await bcrypt.compare(password, user.password);
if (!isPasswordValid) {
return res.status(401).json({ message: 'Invalid password' });
}
res.status(200).json({ message: 'Login successful' });
} catch (error) {
console.error('Error logging in:', error);
res.status(500).json({ message: 'Internal server error' });
}
});
app.get('/products',async (req,res)=>{
try{
const products = await Product.find();
res.status(200).json(products);
}catch(error){
console.error('Error getting products:',error);
res.status(500).json({message:'Internal server error'});
}
})
app.post('/products',async (req,res)=>{
try{
const {name,price,quantity} = req.body;
const newProduct = new Product({name,price,quantity});
await newProduct.save();
res.status(201).json({message:'Product added successfully'});
}catch(error){
console.error('Error adding product:',error);
res.status(500).json({message:'Internal server error'});
}
})
app.put('/products/:id',async (req,res)=>{
try{
const {name,price,quantity} = req.body;
await Product.findByIdAndUpdate(req.params.id,{name,price,quantity});
res.status(200).json({message:'Product updated successfully'});
}catch(error){
console.error('Error updating product:',error);
res.status(500).json({message:'Internal server error'});
}
})
app.delete('/products/:id',async (req,res)=>{
try{
await Product.findByIdAndDelete(req.params.id);
res.status(200).json({message:'Product deleted successfully'});
}catch(error){
console.error('Error deleting product:',error);
res.status(500).json({message:'Internal server error'});
}
})
// Start the server
app.listen(3000, () => {
console.log('Server started on port 3000');
const express = require('express');
const mongoose = require('mongoose');
const bcrypt = require('bcrypt');
const cors = require('cors');

// Import required modules

// Create an Express app
const app = express();

// Enable CORS
app.use(express.json());
app.use(cors());

// Connect to MongoDB
mongoose.connect('mongodb://localhost:27017/cafe', { useNewUrlParser: true, useUnifiedTopology: true })
.then(() => {
console.log('Connected to MongoDB');
})
.catch((error) => {
console.error('Error connecting to MongoDB:', error);
});

// Define a user schema
const userSchema = new mongoose.Schema({
username: { type: String, required: true },
password: { type: String, required: true }
});

// Define a user model
const User = mongoose.model('User', userSchema);
const productSchema = new mongoose.Schema({
name: { type: String, required: true },
price: { type: Number, required: true },
quantity: { type: Number, required: true }
});
const Product = mongoose.model('Product', productSchema);
// Register a new user
app.post('/register', async (req, res) => {
try {
const { username, password } = req.body;

// Check if the username already exists
const existingUser = await User.findOne({ username });
if (existingUser) {
return res.status(400).json({ message: 'Username already exists' });
}

// Hash the password
const hashedPassword = await bcrypt.hash(password, 10);

// Create a new user
const newUser = new User({ username, password: hashedPassword });
await newUser.save();

res.status(201).json({ message: 'User registered successfully' });
} catch (error) {
console.error('Error registering user:', error);
res.status(500).json({ message: 'Internal server error' });
}
});

// User login
app.post('/login', async (req, res) => {
try {
const { username, password } = req.body;

// Find the user by username
const user = await User.findOne({ username });
if (!user) {
return res.status(404).json({ message: 'User not found' });
}

// Compare the password
const isPasswordValid = await bcrypt.compare(password, user.password);
if (!isPasswordValid) {
return res.status(401).json({ message: 'Invalid password' });
}

res.status(200).json({ message: 'Login successful' });
} catch (error) {
console.error('Error logging in:', error);
res.status(500).json({ message: 'Internal server error' });
}
});

app.get('/products',async (req,res)=>{
try{
const products = await Product.find();
res.status(200).json(products);
}catch(error){
console.error('Error getting products:',error);
res.status(500).json({message:'Internal server error'});
}
})

app.post('/products',async (req,res)=>{
try{
const {name,price,quantity} = req.body;
const newProduct = new Product({name,price,quantity});
await newProduct.save();
res.status(201).json({message:'Product added successfully'});
}catch(error){
console.error('Error adding product:',error);
res.status(500).json({message:'Internal server error'});
}
})

app.put('/products/:id',async (req,res)=>{
try{
const {name,price,quantity} = req.body;
await Product.findByIdAndUpdate(req.params.id,{name,price,quantity});
res.status(200).json({message:'Product updated successfully'});
}catch(error){
console.error('Error updating product:',error);
res.status(500).json({message:'Internal server error'});
}
})

app.delete('/products/:id',async (req,res)=>{
try{
await Product.findByIdAndDelete(req.params.id);
res.status(200).json({message:'Product deleted successfully'});
}catch(error){
console.error('Error deleting product:',error);
res.status(500).json({message:'Internal server error'});
}
})
// Start the server
app.listen(3000, () => {
console.log('Server started on port 3000');
});
80 changes: 80 additions & 0 deletions ‎Data-Structures-and-Algorithms-for-Interviews/Main.java
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Original file line number Diff line number Diff line change
@@ -0,0 +1,80 @@
// Following program is a Java implementation
// of Rabin Karp Algorithm given in the CLRS book

public class Main {
// d is the number of characters in the input alphabet
public final static int d = 256;

/* pat -> pattern
txt -> text
q -> A prime number
*/
static void search(String pat, String txt, int q)
{
int M = pat.length();
int N = txt.length();
int i, j;
int p = 0; // hash value for pattern
int t = 0; // hash value for txt
int h = 1;

// The value of h would be "pow(d, M-1)%q"
for (i = 0; i < M - 1; i++)
h = (h * d) % q;

// Calculate the hash value of pattern and first
// window of text
for (i = 0; i < M; i++) {
p = (d * p + pat.charAt(i)) % q;
t = (d * t + txt.charAt(i)) % q;
}

// Slide the pattern over text one by one
for (i = 0; i <= N - M; i++) {

// Check the hash values of current window of
// text and pattern. If the hash values match
// then only check for characters one by one
if (p == t) {
/* Check for characters one by one */
for (j = 0; j < M; j++) {
if (txt.charAt(i + j) != pat.charAt(j))
break;
}

// if p == t and pat[0...M-1] = txt[i, i+1,
// ...i+M-1]
if (j == M)
System.out.println(
"Pattern found at index " + i);
}

// Calculate hash value for next window of text:
// Remove leading digit, add trailing digit
if (i < N - M) {
t = (d * (t - txt.charAt(i) * h)
+ txt.charAt(i + M))
% q;

// We might get negative value of t,
// converting it to positive
if (t < 0)
t = (t + q);
}
}
}

/* Driver Code */
public static void main(String[] args)
{
String txt = "GEEKS FOR GEEKS";
String pat = "GEEK";

// A prime number
int q = 101;

// Function Call
search(pat, txt, q);
}
}