Submission #1037720

#	Time	Username	Problem	Language	Result	Execution time	Memory
1037720		MilosMilutinovic	Text editor (CEOI24_editor)	C++14	100 / 100	2527 ms	271528 KiB

Main

#include <bits/stdc++.h>

using namespace std;

const int MAX = 1000100;
const int L = 21;
const int inf = (int) 1e9;

int n, sx, sy, fx, fy;
int l[MAX], logs[MAX], mn[MAX][L], sz[MAX];
int prv[MAX], nxt[MAX];
vector<int> pos[MAX], dist[MAX];
priority_queue<array<int, 3>> pq;

int Query(int l, int r) {
  int k = logs[r - l + 1];
  return min(mn[l][k], mn[r - (1 << k) + 1][k]);
}

void Update(int i, int j, int d) {
  if (dist[i][j] > d) {
    dist[i][j] = d;
    pq.push({-dist[i][j], i, j});
  }
}

int Index(int i, int v) {
  return (int) (lower_bound(pos[i].begin(), pos[i].end(), v) - pos[i].begin());
}

bool Has(int i, int v) {
  int idx = Index(i, v);
  return 0 <= idx && idx < sz[i] && (pos[i][idx] == v);
}

int FindL(int i, int v) {
  if (v == 0) {
    return -1;
  }
  if (v == l[i]) {
    return prv[i];
  }
  int low = 0, high = i - 1, p = -1;
  while (low <= high) {
    int mid = (low + high) >> 1;
    if (Query(mid, i - 1) <= v) {
      p = mid;
      low = mid + 1;
    } else {
      high = mid - 1;
    }
  }
  return p;
}

int FindR(int i, int v) {
  if (v == 0) {
    return n;
  }
  if (v == l[i]) {
    return nxt[i];
  }
  int low = i + 1, high = n - 1, p = n;
  while (low <= high) {
    int mid = (low + high) >> 1;
    if (Query(i + 1, mid) <= v) {
      p = mid;
      high = mid - 1;
    } else {
      low = mid + 1;
    }
  }
  return p;
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> n;
  cin >> sx >> sy;
  --sx; --sy;
  cin >> fx >> fy;
  --fx; --fy;
  for (int i = 0; i < n; i++) {
    cin >> l[i];
  }
  {
    vector<int> stk;
    for (int i = 0; i < n; i++) {
      while (!stk.empty() && l[stk.back()] > l[i]) {
        stk.pop_back();
      }
      prv[i] = (stk.empty() ? -1 : stk.back());
      stk.push_back(i);
    }
  }
  {
    vector<int> stk;
    for (int i = n - 1; i >= 0; i--) {
      while (!stk.empty() && l[stk.back()] > l[i]) {
        stk.pop_back();
      }
      nxt[i] = (stk.empty() ? n : stk.back());
      stk.push_back(i);
    }
  }
  for (int i = 0; i < n; i++) {
    if (i != fx && l[i] <= l[fx]) {
      pos[fx].push_back(l[i]);
    }
  }
  for (int i = 0; i < n; i++) {
    pos[i].push_back(0);
    pos[i].push_back(l[i]);
    if (sy <= l[i]) {
      pos[i].push_back(sy);
    }
    if (fy <= l[i]) {
      pos[i].push_back(fy);
    }
    sort(pos[i].begin(), pos[i].end());
    pos[i].erase(unique(pos[i].begin(), pos[i].end()), pos[i].end());
  }
  for (int i = 0; i < n; i++) {
    sz[i] = (int) pos[i].size();
  }
  for (int i = 2; i <= n; i++) {
    logs[i] = logs[i >> 1] + 1;
  }
  for (int i = 0; i < n; i++) {
    mn[i][0] = l[i];
  }
  for (int j = 1; j < L; j++) {
    for (int i = 0; i + (1 << j) <= n; i++) {
      mn[i][j] = min(mn[i][j - 1], mn[i + (1 << (j - 1))][j - 1]);
    }
  }
  for (int i = 0; i < n; i++) {
    dist[i] = vector<int>(sz[i], inf);
  }
  for (int i = 0; i < sz[sx]; i++) {
    if (pos[sx][i] == sy) {
      dist[sx][i] = 0;
      pq.push({0, sx, i});
    }
  }
  while (!pq.empty()) {
    int d = -pq.top()[0];
    int i = pq.top()[1];
    int j = pq.top()[2];
    pq.pop();
    if (dist[i][j] != d) {
      continue;
    }
    if (j > 0) {
      Update(i, j - 1, dist[i][j] + pos[i][j] - pos[i][j - 1]);
    } else if (i > 0) {
      Update(i - 1, sz[i - 1] - 1, dist[i][j] + 1);
    }
    if (j + 1 < sz[i]) {
      Update(i, j + 1, dist[i][j] + pos[i][j + 1] - pos[i][j]);
    } else if (i + 1 < n) {
      Update(i + 1, 0, dist[i][j] + 1);
    }
    if (i > 0 && Has(i - 1, pos[i][j])) {
      Update(i - 1, Index(i - 1, pos[i][j]), dist[i][j] + 1);
    }
    if (i + 1 < n && Has(i + 1, pos[i][j])) {
      Update(i + 1, Index(i + 1, pos[i][j]), dist[i][j] + 1);
    } 
    {
      int idx = FindL(i, pos[i][j]);
      if (idx != -1) {
        Update(idx, sz[idx] - 1, dist[i][j] + i - idx);
      }
      if (idx < fx && fx < i && Has(fx, pos[i][j])) {
        Update(fx, Index(fx, pos[i][j]), dist[i][j] + i - fx);
      }
    } 
    {
      int idx = FindR(i, pos[i][j]);
      if (idx != n) {
        Update(idx, sz[idx] - 1, dist[i][j] + idx - i);
      }
      if (i < fx && fx < idx && Has(fx, pos[i][j])) {
        Update(fx, Index(fx, pos[i][j]), dist[i][j] + fx - i);
      }
    } 
  }
  for (int i = 0; i < sz[fx]; i++) {
    if (pos[fx][i] == fy) {
      cout << dist[fx][i] << '\n';
    }
  }
  return 0;
}

• Subtask 0: 0 / 0
• Subtask 1: 5 / 5
• Subtask 2: 14 / 14
• Subtask 3: 26 / 26
• Subtask 4: 11 / 11
• Subtask 5: 44 / 44