siddhantkushwaha

from scrapy.crawler import CrawlerProcess
from scrapy_tasks.spiders.trial import *


class CustomCrawler:

    def __init__(self):
        self.output = None
        self.process = CrawlerProcess(settings={'LOG_ENABLED': False})

siddhantkushwaha

sudo rm /var/lib/apt/lists/lock
sudo rm /var/cache/apt/archives/lock
sudo rm /var/lib/dpkg/lock

siddhantkushwaha

def isSafe(board, row, col):

    for i in range(col):
        if board[row][i] == 'Q':
            return False

    i = row
    j = col
    while i >= 0 and j >= 0:
        if board[i][j] == 'Q':

siddhantkushwaha

def solve(n, o, c, res):
    if len(res) == 2*n:
        yield res

    if o > 0:
        yield from solve(n, o-1, c, res+'(')
    # derived from c > 0 and n-o > n-c
    if c > o:
        yield from solve(n, o, c-1, res+')')

siddhantkushwaha

/*

Bitmasks are cool. A bitmask is a string of binary bits (0s and 1s). For example: "01010" is a bitmask. 
Kuldeep is a naughty but brilliant computer scientist. In his free time, he writes some random programs 
to play with bitmasks. He has a PhD student under him and to test him (and entertain himself), 
he has given him the following task: Given a number N, write a bitmask of length N containing all 0s.
Now, you are given Q operations. Each operation contains two numbers (l, r) as input. 

An operation can be one of the following:
Update operation: Take the XOR of all the bits in the bitmask from index l to r (both inclusive) with 1.

siddhantkushwaha

#include "bits/stdc++.h"
using namespace std;

int partition(int a[], int low, int high) {
    /* try with different values of p in range [low, high] */
    int p = (low + high) / 2;

    int i = low;
    int j = high;
    while (1) {

siddhantkushwaha

int longestPalindromeSubsequence(string A) {
  
    int n = A.length();
    int dp[3][n];

    int res = 1;
    for (int l = 1; l <= n; l++) {
        int idx = (l - 1) % 3;
        for (int left = 1; left <= n - l + 1; left++) {
            int right = left + l - 1;

siddhantkushwaha

/*
    Hash each subtree recursively and check if that hash already exists.
*/

string check_dup(node *root, set<string> &subtrees, int &duplicate_exists) {
    if (root == NULL)
        return "#";

    string hash_left = check_dup(root->left, subtrees, duplicate_exists);
    string hash_right = check_dup(root->right, subtrees, duplicate_exists);

siddhantkushwaha

typedef vector<vector<int>> graph;
graph create(int n, vector<vector<int>> &edges) {

    graph adj(n, vector<int>(0));
    for(auto e : edges) {
        adj[e[0]].push_back(e[1]);
        adj[e[1]].push_back(e[0]);
    }
    return adj;
}

siddhantkushwaha

class DSU {
   private:
    vector<int> arr;
    vector<int> size;

   public:
    DSU(int n) {
        arr.resize(n);
        for (int i = 0; i < n; i++) arr[i] = i;
        size.resize(n, 1);