Competitive_Programming/Structures/mo.cpp at master · jonh14lk/Competitive_Programming · GitHub

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#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

template <class T>
using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

#define PI acos(-1)
#define pb push_back
#define int long long int
#define pi pair<int, int>
#define pii pair<int, pi>
#define fir first
#define sec second
#define MAXN 500005
#define mod 1000000007

int n, q;
int v[MAXN];

namespace mo
{
  struct query
  {
    int idx, l, r;
  };

  int block;
  vector<query> queries;
  vector<int> ans;

  // bool cmp(query &x, query &y) essa funcao de ordenacao pode funcionar em caso de TLE
  // {
  //   int ablock = x.l / MAGIC, bblock = y.l / MAGIC;
  //   if (ablock != bblock)
  //     return ablock < bblock;
  //   if (ablock & 1)
  //     return x.r < y.r;
  //   return x.r > y.r;
  // }
  bool cmp(query &x, query &y)
  {
    if (x.l / block != y.l / block)
      return x.l / block < y.l / block;
    return x.r < y.r;
  }
  void run()
  {
    block = (int)sqrt(n);
    sort(queries.begin(), queries.end(), cmp);
    ans.resize(queries.size());
    int cl = 0, cr = -1, sum = 0;
    auto add = [&](int x)
    {
      sum += x;
    };
    auto rem = [&](int x)
    {
      sum -= x;
    };
    for (int i = 0; i < queries.size(); i++)
    {
      while (cl > queries[i].l)
      {
        cl--;
        add(v[cl]);
      }
      while (cr < queries[i].r)
      {
        cr++;
        add(v[cr]);
      }
      while (cl < queries[i].l)
      {
        rem(v[cl]);
        cl++;
      }
      while (cr > queries[i].r)
      {
        rem(v[cr]);
        cr--;
      }
      ans[queries[i].idx] = sum;
    }
  }
}
signed main()
{
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> n >> q;
  for (int i = 0; i < n; i++)
    cin >> v[i];
  for (int i = 0; i < q; i++)
  {
    mo::query curr;
    cin >> curr.l >> curr.r;
    curr.r--;
    curr.idx = i;
    mo::queries.pb(curr);
  }
  mo::run();
  for (auto const &i : mo::ans)
    cout << i << endl;
}
// to test: https://judge.yosupo.jp/problem/static_range_sum