Submission #399807

#	Time	Username	Problem	Language	Result	Execution time	Memory
399807		anayk	The short shank; Redemption (BOI21_prison)	C++14	80 / 100	2045 ms	68076 KiB

prison

#include <iostream>
#include <vector>
#include <set>

#define int long long

#define left (id+1)
#define mid ((l+r)/2)
#define right (id+2*(mid-l+1))

const int MAXN = 2000006;

int n, d, t;

int par[MAXN];
int min[MAXN], max[MAXN], tar[MAXN];
std::set<std::pair<int, int> > best;

int root(int x) {
  if(par[x] < 0)
    return x;
  return par[x] = root(par[x]);
}

void merge(int u, int v) {
  u = root(u);
  v = root(v);

  if(u == v)
    return;

  if(par[u] > par[v])
    u ^= v ^= u ^= v;

  par[u] += par[v];
  par[v] = u;
  tar[u] = std::max(tar[u], tar[v]);
  max[u] = std::max(max[u], max[v]);
  min[u] = std::min(min[u], min[v]);
}

struct seg
{
  std::vector<int> arr, lazy;

  void push(int id, int l, int r) {
    if(lazy[id]) {
      lazy[id] = 0;
      lazy[left] = lazy[right] = 1;
      arr[left] = mid-l+1;
      arr[right] = r-mid;
    }
  }

  void update(int x, int y, int id = 0, int l = 0, int r = n-1) {
    if(y < l || r < x)
      return;

    if(x <= l && r <= y) {
      arr[id] = r-l+1;
      lazy[id] = 1;
      return;
    }

    push(id, l, r);
    update(x, y, left, l, mid);
    update(x, y, right, mid+1, r);

    arr[id] = arr[left] + arr[right];
  }

  int query(int x, int y, int id = 0, int l = 0, int r = n-1) {
    if(y < l || r < x)
      return 0;

    if(x <= l && r <= y) {
      return arr[id];
    }

    push(id, l, r);
    return query(x, y, left, l, mid) + query(x, y, right, mid+1, r);
  }
};

seg tree;

int getL(int x) {
  if(min[x] == 0)
    return -1;
  return root(min[x]-1);
}

int getR(int x) {
  if(max[x] == n-1)
    return -1;
  return root(max[x]+1);
}

void tog(int x, int y) {
  int nex = getR(x);
  if(nex == -1)
    return;
  int r = std::min(tar[x], max[nex]);
  int l = min[nex];

  int ch = r-l+1-tree.query(l, r);
  if(y == 1)
    best.insert({ch, x});
  else {
    best.erase({ch, x});
    if(y == 0) tree.update(l, r);
  }
}

signed main() {
  std::ios::sync_with_stdio(false);
  std::cin.tie(0);

  std::cin >> n >> d >> t;

  tree.arr = tree.lazy = std::vector<int>(2*n-1, 0);

  for(int i = 0; i < n; i++) {
    int val;
    std::cin >> val;
    par[i] = -1;
    min[i] = max[i] = i;
    tar[i] = i+t-val;
    if(tar[i] >= i)
      tree.update(i, i);
  }

  for(int i = 0; i+1 < n; i++)
    tog(i, 1);

  while(d < n-1) {
    int cur = (*best.begin()).second;
    int bef = getL(cur);
    int af = getR(cur);

    if(bef != -1)
      tog(bef, -1);
    tog(af, -1);
    tog(cur, 0);

    merge(cur, af);
    cur = root(cur);
    if(getR(cur) != -1)
      tog(cur, 1);

    if(bef != -1)
      tog(bef, 1);
    d++;
  }

  std::cout << tree.query(0, n-1) << std::endl;

  return 0;
}

• Subtask 1: 15 / 15
• Subtask 2: 10 / 10
• Subtask 3: 20 / 20
• Subtask 4: 10 / 10
• Subtask 5: 25 / 25
• Subtask 6: 0 / 20