Submission #797331

#	Time	Username	Problem	Language	Result	Execution time	Memory
797331		Sam_a17	Election (BOI18_election)	C++17	100 / 100	535 ms	52992 KiB

election

#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
// #include <atcoder/all>
#include <cstdio>
using namespace std;
 
#ifndef ONLINE_JUDGE
#define dbg(x) cerr << #x <<" "; print(x); cerr << endl;
#else
#define dbg(x)
#endif
 
#define sz(x) (int((x).size()))
#define len(x) (int)x.length()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define clr(x) (x).clear()
#define blt(x) __builtin_popcount(x)
#define uniq(x) x.resize(unique(all(x)) - x.begin());
 
#define pb push_back
#define popf pop_front
#define popb pop_back
#define ld long double
#define ll long long
 
void print(long long t) {cerr << t;}
void print(int t) {cerr << t;}
void print(string t) {cerr << t;}
void print(char t) {cerr << t;}
void print(double t) {cerr << t;}
void print(unsigned long long t) {cerr << t;}
void print(long double t) {cerr << t;}
 
template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T> void print(T v[],T n) {cerr << "["; for(int i = 0; i < n; i++) {cerr << v[i] << " ";} cerr << "]";}
template <class T, class V> void print(pair <T, V> p) {cerr << "{"; print(p.first); cerr << ","; print(p.second); cerr << "}";}
template <class T> void print(vector <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(deque <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(set <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(multiset <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void print(map <T, V> v) {cerr << "[ "; for (auto i : v) {print(i); cerr << " ";} cerr << "]";}
 
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define nl '\n'
 
// for random generations
mt19937 myrand(chrono::steady_clock::now().time_since_epoch().count());
// mt19937 myrand(131);
 
// for grid problems
int dx[8] = {1,0,-1,0,1,-1,1,-1};
int dy[8] = {0,1,0,-1,1,1,-1,-1};
char ch[4] = {'v', '>', '^', '<'};
 
long long ka() {
    long long x = 0;
    bool z = false;
    while (1)
    {
        char y = getchar();
        if (y == '-')
            z = true;
        else if ('0' <= y && y <= '9')
            x = x * 10 + y - '0';
        else
        {
            if (z)
                x *= -1;
            return x;
        }
    }
}
 
// lowest / (1 << 17) >= 1e5 / (1 << 18) >= 2e5 / (1 << 21) >= 1e6
void fastIO() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr); cout.tie(nullptr);
}
// file in/out
void setIO(string str = "") {
  fastIO();
 
  if (str != "") {
    freopen((str + ".in").c_str(), "r", stdin);
    freopen((str + ".out").c_str(), "w", stdout);
  } else if(str == "input") {
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
  }
}
 
// Indexed Set
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
 
const int N = 5e5 + 10;
vector<pair<int, int>> pp[N];
int ans[N];

struct segtree {
  struct node {
    long long sum, suffix;
  };

  node combine (node a, node b) {
    node c;
    c.sum = a.sum + b.sum;
    c.suffix = min(b.sum + a.suffix, b.suffix);
    return c;
  }

  vector<node> mTree;
  int size;

  void init(ll n) {
    size = 1;
    while(size < n)  {
      size *= 2;
    }
    mTree.assign(2 * size - 1, {0, 0});
  }

  void set(int u, ll v, int x, int lx, int rx) {
    if(rx - lx == 1) {
      mTree[x] = {v, min(0ll, v)};
      return;
    }

    int m = (lx + rx) / 2;
    if(u < m) {
      set(u, v, 2 * x + 1, lx, m);
    }else {
      set(u, v, 2 * x + 2, m, rx);
    }
    mTree[x] = combine(mTree[2 * x + 1], mTree[2 * x + 2]);
  }

  void set(int u, ll v) {
    set(u, v, 0, 0, size);
  }

  node range (int l, int r, int x, int lx, int rx) {
    if(l >= rx || lx >= r) {
      return {0, 0};
    }

    if(lx >= l && r >= rx) {
      return mTree[x];
    }

    int m = (rx + lx) / 2;
    node s1 = range(l, r, 2 * x + 1, lx, m);
    node s2 = range(l, r, 2 * x + 2, m, rx);
    return combine(s1, s2);
  }

  node range(int l, int r) {
    return range(l, r, 0, 0, size);
  }
};

segtree seg;

void solve_() {
  int n; cin >> n;
  string s; cin >> s;
 
  int q; cin >> q;
  for(int i = 1; i <= q; i++) {
    int l, r; cin >> l >> r;
    pp[l].emplace_back(r, i);
  }

  seg.init(n + 1);
  for(int i = 0; i < n; i++) {
    if(s[i] == 'T') {
      seg.set(i + 1, -1);
    } else {
      seg.set(i + 1, 1);
    }
  }

  vector<int> ts;
  for(int i = n; i >= 1; i--) {
    if(s[i - 1] == 'T') {
      ts.push_back(i);
      seg.set(i, 0);
    } else if(!ts.empty()) {
      seg.set(ts.back(), -1);
      ts.pop_back();
    }

    for(auto j: pp[i]) {
      int cur = seg.range(i, j.first + 1).suffix;
      if(cur < 0) {
        cur = -cur;
      } else {
        cur = 0;
      }

      ans[j.second] = cur + upper_bound(rall(ts), j.first) - ts.rbegin();
    }
  }

  for(int i = 1; i <= q; i++) {
    cout << ans[i] << '\n';
  }
}
 
int main() {
  setIO();
 
  auto solve = [&](int test_case)-> void {
    while(test_case--) {
      solve_();
    }
  };
 
  int test_cases = 1;
  // cin >> test_cases;
  solve(test_cases);
 
  return 0;
} 

Compilation message (stderr)

election.cpp: In function 'void setIO(std::string)':
election.cpp:90:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   90 |     freopen((str + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
election.cpp:91:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   91 |     freopen((str + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
election.cpp:93:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   93 |     freopen("input.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
election.cpp:94:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   94 |     freopen("output.txt", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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