parallel_bs.cpp

#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")

#include <bits/stdc++.h>
//#include <ext/pb_ds/assoc_container.hpp> //required
//#include <ext/pb_ds/tree_policy.hpp> //required

//using namespace __gnu_pbds; //required 
using namespace std;
//template <typename T> using ordered_set =  tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>; 

// ordered_set <int> s;
// s.find_by_order(k); returns the (k+1)th smallest element
// s.order_of_key(k); returns the number of elements in s strictly less than k

#define pb               push_back
#define mp(x,y)          make_pair(x,y)
#define all(x)           x.begin(), x.end()
#define print(vec,l,r)   for(int i = l; i <= r; i++) cout << vec[i] <<" "; cout << endl;
#define input(vec,N)     for(int i = 0; i < (N); i++) cin >> vec[i];
#define leftmost_bit(x)  (63-__builtin_clzll(x))
#define rightmost_bit(x) __builtin_ctzll(x) // count trailing zeros
#define set_bits(x)      __builtin_popcountll(x) 
#define pow2(i)          (1LL << (i))
#define is_on(x, i)      ((x) & pow2(i)) // state of the ith bit in x
#define set_on(x, i)     ((x) | pow2(i)) // returns integer x with ith bit on
#define set_off(x, i)    ((x) & ~pow2(i)) // returns integer x with ith bit off

#ifdef LOCAL_DEBUG
	#define debug(...) logger(#__VA_ARGS__, __VA_ARGS__)
#else
	#define debug(...) ;
#endif
  
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
// auto dist = uniform_int_distribution<int>(l, r);
// use int a = dist(rng) to get a random number between [l,r] inclusive
template<typename ...Args>
void logger(string vars, Args&&... values) {
    cerr << vars << " = ";
    string delim = "";
    (..., (cerr << delim << values, delim = ", "));
	cerr << endl;
}

typedef long long int ll;
typedef long double ld;

const int MOD = 1e9+7; // 998244353;
const int MX = 2e5+5;
const ll INF = 1e18; // not too close to LLONG_MAX
const ld PI = acos((ld)-1);
const ld EPS = 1e-8;
const int dx[4] = {1,0,-1,0}, dy[4] = {0,1,0,-1}; // for every grid problem!!

// highly risky #defines
// #define int ll // disable when you want to make code a bit faster
#define endl '\n' // disable when dealing with interactive problems

typedef vector<int> vi;
typedef pair<int, int> pii;

const int MAXQ = 1 + 1e5;
const int MAXN = 1 + 1e5;
int lo[MAXQ], hi[MAXQ], ans[MAXQ];

vector<int> vec[MAXN];
// vec[mid] holds the value of all queries whose (lo[i] + hi[i])/2 = mid

int N, Q;

void clear(){ // reset
    // reset your data strucutres used. Not low,mid,hi or ans
}

void apply(int idx){ //Apply ith update/query
	
}

bool possible(int idx){ //Check if the condition is satisfied

}	

void work(){
	for(int i = 0; i < N; i++) vec[i].clear();
    for(int i = 0; i < Q; i++){
        if(lo[i] <= hi[i]) vec[(lo[i] + hi[i])/2].pb(i);
    }

	clear();
	for(int mid = 0; mid < N; mid++){
		apply(mid); // apply the mid-th update
		for(int ind: vec[mid]){ //Add appropriate check conditions

            if(possible(ind)){ // is the answer possible after performing the first mid updates
                ans[ind] = mid; // change as needed
                hi[ind] = mid-1;
            }
			else lo[ind] = mid+1;
		}
	}
}

void parallel_binary(){
    for(int i = 0; i < Q; i++){
        lo[i] = 0;
        hi[i] = N-1;
        ans[i] = -1; // impossible case
    }

	bool changed = true;
	while(changed){ // P(logN)
		changed = false;
		
        for(int i = 0; i < Q; i++){
			if(lo[i] <= hi[i]){
				changed = true;
			}	
		}
		work(); // O((N + Q)*cost of data structure)
	}
}	

// ~stolen~ inspired from https://github.com/Ashishgup1/Competitive-Coding/blob/master/Parallel%20Binary%20Search.cpp
void solve(){
	// code starts from here
	//https://pastebin.com/2PAh5pMe
    // check here for implementation

    // Given N updates and Q queries. You know that for a particular query, 
    // f(query, i) becomes true after the ith update.
    // YOu want to find the first i such that f(query, i) is true.
    
    // So for a single query we can binary search on the answer and perform updates one by one.
    // This techinque called parallel binary search does it for all queries with logK factor
    
    
    
}


clock_t startTime;
double getCurrentTime() {
	return (double)(clock() - startTime) / CLOCKS_PER_SEC;
}

signed main(){
 	ios_base::sync_with_stdio(false);
    cin.tie(NULL);
	//startTime = clock();
	// mt19937_64 rnd(time(NULL));

	int T = 1;
	cin >> T;

	while(T--){
		solve();
	}
	
	//cerr << getCurrentTime() << endl;
	return 0;
}