Submission #1093098

#	Time	Username	Problem	Language	Result	Execution time	Memory
1093098		juicy	Election (BOI18_election)	C++17	82 / 100	3064 ms	42984 KiB

election

#include <bits/stdc++.h>

using namespace std;

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif

const int N = 5e5 + 5;

int n, q;
int res[N];
array<int, 2> tr[4 * N];
string s;
vector<array<int, 2>> que[N];

array<int, 2> operator + (const array<int, 2> &lt, const array<int, 2> &rt) {
  return {min(rt[0], lt[0] + rt[1]), lt[1] + rt[1]};
}

void upd(int i, int x, int id = 1, int l = 1, int r = n) {
  if (l == r) {
    tr[id] = {x, x};
    return;
  }
  int m = (l + r) / 2;
  if (i <= m) {
    upd(i, x, id * 2, l, m);
  } else {
    upd(i, x, id * 2 + 1, m + 1, r);
  }
  tr[id] = tr[id * 2] + tr[id * 2 + 1];
}

array<int, 2> qry(int u, int v, int id = 1, int l = 1, int r = n) {
  if (u <= l && r <= v) {
    return tr[id];
  }
  int m = (l + r) / 2;
  if (v <= m) {
    return qry(u, v, id * 2, l, m);
  }
  if (m < u) {
    return qry(u, v, id * 2 + 1, m + 1, r);
  }
  return qry(u, v, id * 2, l, m) + qry(u, v, id * 2 + 1, m + 1, r);
}

int main() {
  ios::sync_with_stdio(false); cin.tie(nullptr);

  cin >> n >> s >> q;
  for (int i = 1; i <= q; ++i) {
    int l, r; cin >> l >> r;
    que[l].push_back({r, i});
  }  
  vector<int> st;
  for (int i = n; i; --i) {
    if (s[i - 1] == 'T') {
      st.push_back(i);
    } else {
      upd(i, 1);
      if (st.size()) {
        upd(st.back(), -1);
        st.pop_back();
      }
    }
    sort(que[i].begin(), que[i].end());
    int k = st.size();
    for (auto [j, id] : que[i]) {
      while (k - 1 >= 0 && st[k - 1] <= j) {
        --k;
      }
      res[id] = st.size() - k + max(0, -qry(i, j)[0]);
    }
  }
  for (int i = 1; i <= q; ++i) {
    cout << res[i] << "\n";
  }
  return 0;
}

• Subtask 1: 28 / 28
• Subtask 2: 54 / 54
• Subtask 3: 0 / 18