DataStructure/SqrtDecomposition/Sqrt.h

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• Last update: 2025-06-11 15:37:14+07:00

Depends on

• template.h

Verified with

• DataStructure/SqrtDecomposition/Point_Add_Range_Sum.test.cpp

Code

#include "../../template.h"

class SimpleSqrt {
public:
    int n, block_sz;
    vector<ll> a, block;

    SimpleSqrt() {}

    SimpleSqrt(int _n): n(_n), a(_n, 0) {
        block_sz = sqrt(_n);
        block.resize(n / block_sz + 1);
    }

    SimpleSqrt(int _n, vector<ll> &arr): n(_n), a(arr) {
        block_sz = sqrt(n);
        block.resize(n / block_sz + 1);
        int cnt = -1;
        for(int i = 0; i < n; i++) {
            if(i % block_sz == 0) cnt++;
            block[cnt] += arr[i];
        }
    }

    ll query(int l, int r) {
        ll sum = 0;
        for(int i = l; i <= r;) {
            if(i % block_sz == 0 && i+block_sz-1 <= r) {
                sum += block[i/block_sz];
                i += block_sz;
            } else {
                sum += a[i];
                i++;
            }
        }
        return sum;
    }

    void add(int pos, int val) {
        int idx = pos / block_sz;
        block[idx] += val;
        a[pos] += val;
    }
};

#line 2 "template.h"

#include <bits/stdc++.h>
using namespace std;
 
#define ll long long
#define MOD (ll)(1e9+7)
#define all(x) (x).begin(),(x).end()
#define unique(x) x.erase(unique(all(x)), x.end())
#define INF32 ((1ull<<31)-1)
#define INF64 ((1ull<<63)-1)
#define inf (ll)1e18

#define vi vector<int>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define fi first
#define se second

const int mod = 998244353;

void solve();

int main(){
    ios_base::sync_with_stdio(false);cin.tie(NULL);
    // cin.exceptions(cin.failbit);
    // int t; cin >> t;
    // while(t--)
        solve();
    cerr << "\nTime run: " << 1000 * clock() / CLOCKS_PER_SEC << "ms" << '\n';
    return 0;
}
#line 2 "DataStructure/SqrtDecomposition/Sqrt.h"

class SimpleSqrt {
public:
    int n, block_sz;
    vector<ll> a, block;

    SimpleSqrt() {}

    SimpleSqrt(int _n): n(_n), a(_n, 0) {
        block_sz = sqrt(_n);
        block.resize(n / block_sz + 1);
    }

    SimpleSqrt(int _n, vector<ll> &arr): n(_n), a(arr) {
        block_sz = sqrt(n);
        block.resize(n / block_sz + 1);
        int cnt = -1;
        for(int i = 0; i < n; i++) {
            if(i % block_sz == 0) cnt++;
            block[cnt] += arr[i];
        }
    }

    ll query(int l, int r) {
        ll sum = 0;
        for(int i = l; i <= r;) {
            if(i % block_sz == 0 && i+block_sz-1 <= r) {
                sum += block[i/block_sz];
                i += block_sz;
            } else {
                sum += a[i];
                i++;
            }
        }
        return sum;
    }

    void add(int pos, int val) {
        int idx = pos / block_sz;
        block[idx] += val;
        a[pos] += val;
    }
};

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