oj.uz

Submission #218120

# Submission time Handle Problem Language Result Execution time Memory
218120 2020-04-01T09:33:55 Z extraterrestrial Candies (JOI18_candies) C++14
100 / 100
 702 ms 46328 KB 
#include <bits/stdc++.h>
typedef long long ll;
typedef long double ld;
using namespace std;
#define F first
#define S second
#define pb push_back
#define all(x) (x).begin(), (x).end()
#define SZ(x) (int)(x).size()
#define int ll

mt19937 rnd(239);

struct DSU {
  vector<int> p, l, r;
  DSU(int n) {
    p.resize(n + 1);
    l.resize(n + 1);
    r.resize(n + 1);
    iota(all(p), 0);
    iota(all(l), 0);
    iota(all(r), 0);
  }
  int find(int v) {
    return p[v] == v ? v : p[v] = find(p[v]);
  }
  void merge(int a, int b) {
    a = find(a), b = find(b);
    if (a == b) {
      return;
    }
    if (rnd() & 1) {
      swap(a, b);
    }
    p[b] = a;
    l[a] = min(l[a], l[b]);
    r[a] = max(r[a], r[b]);
  }
};

struct ST {
  vector<int> t;
  void init(int n) {
    t.resize(4 * n + 10, -1);
  }
  void push(int v) {
    if (t[v] != -1) {
      t[2 * v] = t[v];
      t[2 * v + 1] = t[v];
      t[v] = -1;
      return;
    }
  }
  void update(int v, int l, int r, int a, int b, int vl) {
    if (l > b || r < a) {
      return;
    }
    if (l >= a && r <= b) {
      t[v] = vl;
      return;
    }
    push(v);
    int mid = (l + r) / 2;
    update(2 * v, l, mid, a, b, vl);
    update(2 * v + 1, mid + 1, r, a, b, vl);
  }
  int get(int v, int l, int r, int need) {
    if (l == r) {
      return t[v];
    }
    push(v);
    int mid = (l + r) / 2;
    if (need <= mid) {
      return get(2 * v, l, mid, need);
    }
    else {
      return get(2 * v + 1, mid + 1, r, need);
    }
  }
  /*void init(int n) {
    t.resize(n + 1);
  }
  void update(int v, int l, int r, int a, int b, int vl) {
    for (int i = a; i <= b; i++) {
      t[i] = vl;
    }
  }
  int get(int v, int l, int r, int need) {
    return t[need];
  }*/
};

ST tree1, tree2;
const int N = 2e5 + 10;
int a[N], pref[N];

inline int get_sum(int l, int r) {
  int rez = pref[r] - pref[l - 1];
  if (l % 2 == 0) {
    rez *= -1;
  }
  return rez;
}

int n;

inline int check(int x) {
  if (x & 1) {
    return tree1.get(1, 1, n, x);
  }
  else {
    return tree2.get(1, 1, n, x);
  }
}

set<int> unmerged[2];

signed main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  cin >> n;
  for (int i = 1; i <= n; i++) {
    cin >> a[i];
  }
  for (int i = 1; i <= n; i++) {
    pref[i] = pref[i - 1];
    if (i & 1) {
      pref[i] += a[i];
    }
    else {
      pref[i] -= a[i];
    }
  }
  for (int i = 1; i + 2 <= n; i++) {
    unmerged[i % 2].insert(i);
  }
  tree1.init(n);
  tree2.init(n);
  DSU kek(n);
  tree1.update(1, 1, n, 1, n, 0);
  tree2.update(1, 1, n, 1, n, 0);
  set<pair<int, int>> can;
  for (int i = 1; i <= n; i++) {
    can.insert({a[i], i});
  }	
  set<pair<int, pair<int, int>>> can_flip;
  int all = 0;
  for (int i = 1; i <= (n + 1) / 2; i++) {
    pair<int, int> mx = {-1e18, 0};
    if (!can.empty()) {
      mx = *(--can.end());
    }
    pair<int, pair<int, int>> mx2 = {-1e18, {0, 0}};
    if (!can_flip.empty()) {
      mx2 = *(--can_flip.end());
    }
    if (mx.F > mx2.F) {
      all += mx.F;
      can.erase(--can.end());
      //cout << 1 << ' ' << mx.S << '\n';
      if (mx.S > 1 && can.find({a[mx.S - 1], mx.S - 1}) != can.end()) {
        can.erase({a[mx.S - 1], mx.S - 1});
      }
      if (mx.S < n && can.find({a[mx.S + 1], mx.S + 1}) != can.end()) {
        can.erase({a[mx.S + 1], mx.S + 1});
      }
      if (mx.S & 1) {
        tree1.update(1, 1, n, mx.S, mx.S, 1);
      }
      else {
        tree2.update(1, 1, n, mx.S, mx.S, 1);
      }

      if (mx.S > 2 && check(mx.S - 2)) {
        int comp = kek.find(mx.S - 2);
        if (kek.l[comp] > 1 && kek.r[comp] < n) {
          can_flip.erase(make_pair(get_sum(kek.l[comp] - 1, kek.r[comp] + 1), make_pair(kek.l[comp], kek.r[comp])));
        }
        unmerged[mx.S % 2].erase(mx.S - 2);
        kek.merge(mx.S, mx.S - 2);
      }
      if (mx.S + 2 <= n && check(mx.S + 2)) {
        int comp = kek.find(mx.S + 2);
        if (kek.l[comp] > 1 && kek.r[comp] < n) {
          can_flip.erase(make_pair(get_sum(kek.l[comp] - 1, kek.r[comp] + 1), make_pair(kek.l[comp], kek.r[comp])));
        }
        unmerged[mx.S % 2].erase(mx.S);
        kek.merge(mx.S, mx.S + 2);
      }
      int comp = kek.find(mx.S);
      if (kek.l[comp] > 1 && kek.r[comp] < n) {
        can_flip.insert(make_pair(get_sum(kek.l[comp] - 1, kek.r[comp] + 1), make_pair(kek.l[comp], kek.r[comp])));
      }
    }
    else {
      //cout << i << ' ' << 2 << '\n';
      all += mx2.F;
      int L = mx2.S.F, R = mx2.S.S;
      //cout << L << ' ' << R << '\n';
      if (L > 2 && can.find({a[L - 2], L - 2}) != can.end()) {
        can.erase({a[L - 2], L - 2});
      }
      if (R + 2 <= n && can.find({a[R + 2], R + 2}) != can.end()) {
        can.erase({a[R + 2], R + 2});
      }
      if (L & 1) {
        tree1.update(1, 1, n, L, R, 0);
        tree2.update(1, 1, n, L - 1, R + 1, 1);
      } 
      else {
        tree2.update(1, 1, n, L, R, 0);
        tree1.update(1, 1, n, L - 1, R + 1, 1);
      }
      can_flip.erase(--can_flip.end());
      L--, R++;
      for (;;) {
        auto it = unmerged[L % 2].lower_bound(L);
        if (it == unmerged[L % 2].end() || *it > R - 2) {
          break;
        }
        kek.merge(*it, *it + 2);
        unmerged[L % 2].erase(it);
        //cout << "C " << *it << '\n';
      }
      if (L > 2 && check(L - 2)) {
        int comp = kek.find(L - 2);
        if (kek.l[comp] > 1 && kek.r[comp] < n) {
          can_flip.erase(make_pair(get_sum(kek.l[comp] - 1, kek.r[comp] + 1), make_pair(kek.l[comp], kek.r[comp])));
        }
        unmerged[L % 2].erase(L - 2);
        kek.merge(L, L - 2);
      }
      if (R + 2 <= n && check(R + 2)) {
        int comp = kek.find(R + 2);
        if (kek.l[comp] > 1 && kek.r[comp] < n) {
          can_flip.erase(make_pair(get_sum(kek.l[comp] - 1, kek.r[comp] + 1), make_pair(kek.l[comp], kek.r[comp])));
        }
        unmerged[R % 2].erase(R);
        kek.merge(R, R + 2);
      }
      int comp = kek.find(L);
      if (kek.l[comp] > 1 && kek.r[comp] < n) {
        can_flip.insert(make_pair(get_sum(kek.l[comp] - 1, kek.r[comp] + 1), make_pair(kek.l[comp], kek.r[comp])));
      } 
    }
    cout << all << '\n';
    /*for (int i = 1; i <= n; i++) {
      cout << check(i) << ' ';
    }
    cout << '\n';*/
  }
}

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 768 KB Output is correct
2 Correct 7 ms 896 KB Output is correct
3 Correct 7 ms 768 KB Output is correct
4 Correct 12 ms 896 KB Output is correct
5 Correct 7 ms 768 KB Output is correct
6 Correct 9 ms 896 KB Output is correct
7 Correct 7 ms 768 KB Output is correct
8 Correct 7 ms 896 KB Output is correct
9 Correct 7 ms 768 KB Output is correct
10 Correct 7 ms 768 KB Output is correct
11 Correct 7 ms 896 KB Output is correct
12 Correct 7 ms 768 KB Output is correct
13 Correct 7 ms 768 KB Output is correct
14 Correct 7 ms 768 KB Output is correct
15 Correct 10 ms 896 KB Output is correct
16 Correct 14 ms 768 KB Output is correct
17 Correct 7 ms 896 KB Output is correct
18 Correct 7 ms 896 KB Output is correct
19 Correct 7 ms 896 KB Output is correct
20 Correct 7 ms 896 KB Output is correct

Subtask #2
92.0 / 92.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 768 KB Output is correct
2 Correct 7 ms 896 KB Output is correct
3 Correct 7 ms 768 KB Output is correct
4 Correct 12 ms 896 KB Output is correct
5 Correct 7 ms 768 KB Output is correct
6 Correct 9 ms 896 KB Output is correct
7 Correct 7 ms 768 KB Output is correct
8 Correct 7 ms 896 KB Output is correct
9 Correct 7 ms 768 KB Output is correct
10 Correct 7 ms 768 KB Output is correct
11 Correct 7 ms 896 KB Output is correct
12 Correct 7 ms 768 KB Output is correct
13 Correct 7 ms 768 KB Output is correct
14 Correct 7 ms 768 KB Output is correct
15 Correct 10 ms 896 KB Output is correct
16 Correct 14 ms 768 KB Output is correct
17 Correct 7 ms 896 KB Output is correct
18 Correct 7 ms 896 KB Output is correct
19 Correct 7 ms 896 KB Output is correct
20 Correct 7 ms 896 KB Output is correct
21 Correct 702 ms 46200 KB Output is correct
22 Correct 673 ms 46072 KB Output is correct
23 Correct 646 ms 46200 KB Output is correct
24 Correct 312 ms 45948 KB Output is correct
25 Correct 311 ms 45944 KB Output is correct
26 Correct 313 ms 45944 KB Output is correct
27 Correct 382 ms 46072 KB Output is correct
28 Correct 375 ms 46072 KB Output is correct
29 Correct 372 ms 46072 KB Output is correct
30 Correct 375 ms 46200 KB Output is correct
31 Correct 376 ms 46072 KB Output is correct
32 Correct 377 ms 46076 KB Output is correct
33 Correct 486 ms 46072 KB Output is correct
34 Correct 486 ms 45944 KB Output is correct
35 Correct 484 ms 46072 KB Output is correct
36 Correct 633 ms 46328 KB Output is correct
37 Correct 639 ms 46328 KB Output is correct
38 Correct 621 ms 46072 KB Output is correct
39 Correct 302 ms 45944 KB Output is correct
40 Correct 300 ms 45944 KB Output is correct
41 Correct 301 ms 45944 KB Output is correct
42 Correct 371 ms 46200 KB Output is correct
43 Correct 373 ms 46072 KB Output is correct
44 Correct 368 ms 46220 KB Output is correct
45 Correct 376 ms 46200 KB Output is correct
46 Correct 370 ms 46072 KB Output is correct
47 Correct 387 ms 46200 KB Output is correct
48 Correct 475 ms 46072 KB Output is correct
49 Correct 478 ms 45948 KB Output is correct
50 Correct 482 ms 45944 KB Output is correct