Submission #1093112

#	Time	Username	Problem	Language	Result	Execution time	Memory
1093112		juicy	Election (BOI18_election)	C++17	100 / 100	406 ms	44804 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();
      }
    }
    for (auto [j, id] : que[i]) {
      int l = 0, r = int(st.size()) - 1, k = 0;
      while (l <= r) {
        int m = (l + r) / 2;
        if (st[m] <= j) {
          k = st.size() - m;
          r = m - 1;
        } else {
          l = m + 1;
        }
      }
      res[id] = 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: 18 / 18