Submission #570594

#	Time	Username	Problem	Language	Result	Execution time	Memory
570594		iancu	Abduction 2 (JOI17_abduction2)	C++14	44 / 100	5045 ms	27960 KiB

abduction2

#include <bits/stdc++.h>

#define NORTH 0
#define SOUTH 1
#define EAST  2
#define WEST  3

using namespace std;

const int N = 5e4 + 5;

struct Node {
  int x, y;
  int val;
  int dir;
  long long dist;

  bool operator<(const Node& n) const {
    return val > n.val;
    //return make_tuple(x, y, dir) < make_tuple(n.x, n.y, n.dir);
  }
};

struct Hasher
{
  long long operator() (const Node& n) const
  {
      return n.dir ^ n.val ^ n.x ^ n.y;
  }
};
struct EqualFn
{
  bool operator() (const Node& n1, const Node& n2) const
  {
    return (n1.x == n2.x) && (n1.y == n2.y) && (n1.val == n2.val) && (n1.dir == n2.dir);
  }
};
struct Hasher2
{
  size_t operator() (const pair<int, int>& v) const
  {
      size_t h = (size_t(v.first)<<32)+size_t(v.second);
      h*=1231231557ull; // "random" uneven integer
      h^=(h>>32);
      return h;
  }
};

int h, w;
int a[N], b[N];

long long solve(int x, int y, int dir) {
  unordered_map<Node, pair<int, int>, Hasher, EqualFn> nxt;
  unordered_map<pair<int, int>, long long, Hasher2> dp;
  int hl, hr, wl, wr;
  long long ans = 0;
  hl = hr = x;
  wl = wr = y;
  if (dir == 0) hl = max(hl - 1, 1);
  else if (dir == 1) hr = min(hr + 1, h);
  else if (dir == 2) wr = min(wr + 1, w);
  else wl = max(wl - 1, 1);
  priority_queue<Node> pq;
  pq.push({x, y, 0, dir, 0});
  while (!pq.empty()) {
    auto n = pq.top();
    //cout << n.x << " " << n.y << " " << n.dir << " " << n.dist << endl;
    pq.pop();
    ans = max(ans, n.dist);

    if (n.dir == NORTH && n.x == 1)
      continue;
    if (n.dir == SOUTH && n.x == h)
      continue;
    if (n.dir == EAST  && n.y == w)
      continue;
    if (n.dir == WEST  && n.y == 1)
      continue;

    if (n.dir == NORTH) {
      if (nxt.find(n) != nxt.end()) {
      } else {
          while (hl > 1 && a[hl] <= b[n.y])
            --hl;
          if (a[hl] <= b[n.y]) {
            ans = max(ans, n.dist + n.x - hl);
            continue;
          }
          nxt[n] = {hl, n.y};
      }
      if (dp[nxt[n]] >= n.dist + n.x - nxt[n].first)
        continue;
      dp[nxt[n]] = n.dist + n.x - nxt[n].first;
      pq.push({nxt[n].first, nxt[n].second, a[nxt[n].first], WEST, n.dist + n.x - nxt[n].first});
      pq.push({nxt[n].first, nxt[n].second, a[nxt[n].first], EAST, n.dist + n.x - nxt[n].first});
    } else if (n.dir == SOUTH) {
      if (nxt.find(n) == nxt.end()) {
        while (hr < h && a[hr] <= b[n.y])
          ++hr;
        if (a[hr] <= b[n.y]) {
          ans = max(ans, n.dist + hr - n.x);
          continue;
        }
        nxt[n] = {hr, n.y};
      }
      if (dp[nxt[n]] >= n.dist + nxt[n].first - n.x)
        continue;
      dp[nxt[n]] = n.dist + nxt[n].first - n.x;
      pq.push({nxt[n].first, nxt[n].second, a[nxt[n].first], WEST, n.dist + nxt[n].first - n.x});
      pq.push({nxt[n].first, nxt[n].second, a[nxt[n].first], EAST, n.dist + nxt[n].first - n.x});
    } else if (n.dir == EAST) {
      if (nxt.find(n) == nxt.end()) {
        while (wr < w && b[wr] <= a[n.x])
          ++wr;
        if (b[wr] <= a[n.x]) {
          ans = max(ans, n.dist + wr - n.y);
          continue;
        }
        nxt[n] = {n.x, wr};
      }
      if (dp[nxt[n]] >= n.dist + nxt[n].second - n.y)
        continue;
      dp[nxt[n]] = n.dist + nxt[n].second - n.y;
      pq.push({nxt[n].first, nxt[n].second, b[nxt[n].second], NORTH, n.dist + nxt[n].second - n.y});
      pq.push({nxt[n].first, nxt[n].second, b[nxt[n].second], SOUTH, n.dist + nxt[n].second - n.y});
    } else {
      if (nxt.find(n) == nxt.end()) {
        while (wl > 1 && b[wl] <= a[n.x])
          --wl;
        if (b[wl] <= a[n.x]) {
          ans = max(ans, n.dist + n.y - wl);
          continue;
        }
        nxt[n] = {n.x, wl};
      }
      if (dp[nxt[n]] >= n.dist + n.y - nxt[n].second)
        continue;
      dp[nxt[n]] = n.dist + n.y - nxt[n].second;
      pq.push({nxt[n].first, nxt[n].second, b[nxt[n].second], NORTH, n.dist + n.y - nxt[n].second});
      pq.push({nxt[n].first, nxt[n].second, b[nxt[n].second], SOUTH, n.dist + n.y - nxt[n].second});
    }
  }
  return ans;
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr), cout.tie(nullptr);
  int q;
  cin >> h >> w >> q;
  for (int i = 1; i <= h; ++i)
    cin >> a[i];
  for (int i = 1; i <= w; ++i)
    cin >> b[i];
  while (q--) {
    int x, y;
    cin >> x >> y;
    long long ans = 0;
    for (int i = 0; i < 4; ++i)
      ans = max(ans, solve(x, y, i));
    cout << ans << "\n";
  }
  return 0;
}

• Subtask 1: 13 / 13
• Subtask 2: 10 / 10
• Subtask 3: 17 / 17
• Subtask 4: 4 / 4
• Subtask 5: 0 / 56