Submission #934413

#	Time	Username	Problem	Language	Result	Execution time	Memory
934413		ind1v	Toll (BOI17_toll)	C++11	100 / 100	266 ms	27604 KiB

toll

#include <bits/stdc++.h>

using namespace std;

const int N = 5e4 + 5;
const int O = 1e4 + 5;
const int K = 6;
const int INF = 1e9;

int k, n, m, o;
vector<array<int, 3>> g[K][N], rg[K][N];
int ans[O];
int d[K][N], rd[K][N];

void bfs(int row, int col, int r) {
  for (int i = 0; i < k; i++) {
    for (int j = col; j <= r; j++) {
      d[i][j] = INF;
    }
  }
  priority_queue<pair<int, pair<int, int>>> pq;
  d[row][col] = 0;
  pq.push({-d[row][col], {row, col}});
  while (!pq.empty()) {
    int cd = -pq.top().first;
    int x = pq.top().second.first;
    int y = pq.top().second.second;
    pq.pop();
    if (cd != d[x][y]) {
      continue;
    }
    for (auto &nxt : g[x][y]) {
      if (nxt[1] > r) {
        continue;
      }
      if (d[nxt[0]][nxt[1]] > d[x][y] + nxt[2]) {
        d[nxt[0]][nxt[1]] = d[x][y] + nxt[2];
        pq.push({-d[nxt[0]][nxt[1]], {nxt[0], nxt[1]}});
      }
    }
  }
}

void sfb(int row, int col, int l) {
  for (int i = 0; i < k; i++) {
    for (int j = col; j >= l; j--) {
      rd[i][j] = INF;
    }
  }
  priority_queue<pair<int, pair<int, int>>> pq;
  rd[row][col] = 0;
  pq.push({-rd[row][col], {row, col}});
  while (!pq.empty()) {
    int cd = -pq.top().first;
    int x = pq.top().second.first;
    int y = pq.top().second.second;
    pq.pop();
    if (cd != rd[x][y]) {
      continue;
    }
    for (auto &nxt : rg[x][y]) {
      if (nxt[1] < l) {
        continue;
      }
      if (rd[nxt[0]][nxt[1]] > rd[x][y] + nxt[2]) {
        rd[nxt[0]][nxt[1]] = rd[x][y] + nxt[2];
        pq.push({-rd[nxt[0]][nxt[1]], {nxt[0], nxt[1]}});
      }
    }
  }
}

void solve(int l, int r, vector<array<int, 5>> &q) {
  if (q.empty()) {
    return;
  }
  int m = (l + r) >> 1;
  vector<array<int, 5>> ql, qr, qc;
  for (auto &x : q) {
    if (x[3] < m) {
      ql.emplace_back(x);
    } else if (x[1] > m) {
      qr.emplace_back(x);
    } else {
      qc.emplace_back(x);
    }
  }
  for (int row = 0; row < k; row++) {
    bfs(row, m, r);
    sfb(row, m, l);
    for (auto &x : qc) {
      ans[x[4]] = min(ans[x[4]], rd[x[0]][x[1]] + d[x[2]][x[3]]);
    }
  }
  solve(l, m - 1, ql);
  solve(m + 1, r, qr);
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cin >> k >> n >> m >> o;
  for (int i = 0; i < m; i++) {
    int a, b, t;
    cin >> a >> b >> t;
    g[a % k][a / k].push_back({b % k, b / k, t});
    rg[b % k][b / k].push_back({a % k, a / k, t});
  }
  vector<array<int, 5>> que(o);
  for (int i = 0; i < o; i++) {
    int a, b;
    cin >> a >> b;
    que[i] = {a % k, a / k, b % k, b / k, i};
  }
  for (int i = 0; i < o; i++) {
    ans[i] = INF;
  }
  solve(0, n - 1, que);
  for (int i = 0; i < o; i++) {
    if (ans[i] == INF) {
      ans[i] = -1;
    }
    cout << ans[i] << '\n';
  }
  return 0;
}

• Subtask 1: 7 / 7
• Subtask 2: 10 / 10
• Subtask 3: 8 / 8
• Subtask 4: 31 / 31
• Subtask 5: 44 / 44