oj.uz

답안 #856933

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
856933 2023-10-04T22:48:07 Z rxlfd314 Valley (BOI19_valley) C++17
100 / 100
 864 ms 176292 KB 
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ari2 = array<int, 2>;

#define vt vector
#define size(x) (int((x).size()))
#define all(x) begin(x), end(x)

#define REP(a, b, c, d) for (int a = (b); (d) > 0 ? a <= (c) : a >= (c); a += (d))
#define FOR(a, b, c) REP(a, b, c, 1)
#define ROF(a, b, c) REP(a, b, c, -1)

#define chmax(a, b) a = a > (b) ? a : (b)
#define chmin(a, b) a = a < (b) ? a : (b)

constexpr int mxN = 100000;
constexpr ll INF = 0x3f3f3f3f3f3f3f3f;
int N, S, Q, E, edges[mxN][2];
vt<ari2> adj[mxN];
int tin[mxN], tout[mxN], timer, lift[mxN][17];
ll depth[mxN];
bool shop[mxN];

void dfs(int i, int p) {
  tin[i] = timer++;
  for (auto [j, v] : adj[i]) {
    if (j == p)
      continue;
    depth[j] = depth[i] + v;
    dfs(j, i);
  }
  tout[i] = timer - 1;
  lift[i][0] = p;
}

bool ia(int a, int b) {
  return tin[a] <= tin[b] && tin[b] <= tout[a];
}

int LCA(int a, int b) {
  if (ia(a, b))
    return a;
  if (ia(b, a))
    return b;
  ROF(i, 16, 0)
    a = ia(lift[a][i], b) ? a : lift[a][i];
  return lift[a][0];
}

ll dist(int a, int b) {
  return depth[a] + depth[b] - 2 * depth[LCA(a, b)];
}

int szs[mxN];
bool dead[mxN];
int gs(int i, int p) {
  szs[i] = 1;
  for (auto [j, _] : adj[i])
    if (!dead[j] && j != p)
      szs[i] += gs(j, i);
  return szs[i];
}

int fc(int i, int n) {
  int p = i;
  bool flag = true;
  while (flag) {
    flag = false;
    for (auto [j, _] : adj[i])
      if (!dead[j] && j != p && szs[j] > n >> 1) {
        p = i;
        i = j;
        flag = true;
        break;
      }
  }
  return i;
}

int pr[mxN];
void cd_init(int i, int p) {
  int c = fc(i, gs(i, i));
  pr[c] = p;
  dead[c] = true;
  for (auto [j, _] : adj[c])
    if (!dead[j])
      cd_init(j, c);
}

struct Node {
  ll val = INF;
  Node *lft = nullptr, *rht = nullptr;
  void upd(int p, ll v, int tl, int tr) {
    if (tl == tr)
      chmin(val, v);
    else {
      int tm = tl + tr >> 1;
      if (p > tm) {
        if (!rht)
          rht = new Node;
        rht->upd(p, v, tm+1, tr);
      } else {
        if (!lft)
          lft = new Node;
        lft->upd(p, v, tl, tm);
      }
      val = min(lft ? lft->val : INF, rht ? rht->val : INF);
    }
  }
  ll qry(int ql, int qr, int tl, int tr) {
    if (tl > qr || tr < ql)
      return INF;
    if (ql <= tl && tr <= qr)
      return val;
    int tm = tl + tr >> 1;
    return min(lft ? lft->qry(ql, qr, tl, tm) : INF, rht ? rht->qry(ql, qr, tm+1, tr) : INF);
  }
} sts[mxN];

void init() {
  dfs(0, 0);
  FOR(j, 1, 16)
    FOR(i, 0, N-1)
      lift[i][j] = lift[lift[i][j-1]][j-1];
  cd_init(0, -1);
  FOR(i, 0, N-1)
    if (shop[i])
      for (int j = i; ~j; j = pr[j])
        sts[j].upd(tin[i], dist(i, j), 0, N-1);
}

signed main() {
#ifndef DEBUG
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
#endif

  cin >> N >> S >> Q >> E, E--;
  FOR(i, 1, N-1) {
    int &a = edges[i][0], &b = edges[i][1], c;
    cin >> a >> b >> c;
    adj[--a].push_back({--b, c});
    adj[b].push_back({a, c});
  }
  FOR(_, 1, S) {
    int v;
    cin >> v;
    shop[--v] = true;
  }
  init();
  
  while (Q--) {
    int x, y;
    cin >> x >> y, y--;
    int a = edges[x][0], b = edges[x][1];
    if (ia(b, a))
      swap(a, b);
    bool in_sub = ia(b, y);
    if (ia(b, E) && in_sub || !ia(b, E) && !in_sub) {
      cout << "escaped\n";
      continue;
    }
    ll ans = INF;
    for (int j = y; ~j; j = pr[j]) {
      if (in_sub ^ ia(b, j))
        continue;
      ll d = dist(j, y);
      if (in_sub)
        ans = min(ans, sts[j].qry(tin[b], tout[b], 0, N-1) + dist(j, y));
      else
        ans = min({ans - d, sts[j].qry(0, tin[b]-1, 0, N-1), sts[j].qry(tout[b]+1, N-1, 0, N-1)}) + d;
    }
    if (ans < INF)
      cout << ans;
    else
      cout << "oo";
    cout << '\n';
  }
}

Compilation message

valley.cpp: In member function 'void Node::upd(int, ll, int, int)':
valley.cpp:98:19: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   98 |       int tm = tl + tr >> 1;
      |                ~~~^~~~
valley.cpp: In member function 'll Node::qry(int, int, int, int)':
valley.cpp:116:17: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  116 |     int tm = tl + tr >> 1;
      |              ~~~^~~~
valley.cpp: In function 'int main()':
valley.cpp:160:18: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
  160 |     if (ia(b, E) && in_sub || !ia(b, E) && !in_sub) {
      |         ~~~~~~~~~^~~~~~~~~

Subtask #1
9.0 / 9.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 4696 KB Output is correct
2 Correct 3 ms 4696 KB Output is correct
3 Correct 3 ms 4700 KB Output is correct
4 Correct 3 ms 4700 KB Output is correct

Subtask #2
27.0 / 27.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 4696 KB Output is correct
2 Correct 3 ms 4696 KB Output is correct
3 Correct 3 ms 4700 KB Output is correct
4 Correct 3 ms 4700 KB Output is correct
5 Correct 1 ms 4700 KB Output is correct
6 Correct 2 ms 4548 KB Output is correct
7 Correct 2 ms 4700 KB Output is correct
8 Correct 2 ms 4696 KB Output is correct
9 Correct 2 ms 4700 KB Output is correct
10 Correct 2 ms 4700 KB Output is correct
11 Correct 2 ms 5208 KB Output is correct
12 Correct 3 ms 5316 KB Output is correct
13 Correct 3 ms 5464 KB Output is correct
14 Correct 2 ms 4956 KB Output is correct

Subtask #3
23.0 / 23.0

# 결과 실행 시간 메모리 Grader output
1 Correct 337 ms 101188 KB Output is correct
2 Correct 540 ms 126228 KB Output is correct
3 Correct 779 ms 144180 KB Output is correct
4 Correct 864 ms 164944 KB Output is correct
5 Correct 747 ms 164512 KB Output is correct
6 Correct 849 ms 176292 KB Output is correct

Subtask #4
41.0 / 41.0

# 결과 실행 시간 메모리 Grader output
1 Correct 3 ms 4696 KB Output is correct
2 Correct 3 ms 4696 KB Output is correct
3 Correct 3 ms 4700 KB Output is correct
4 Correct 3 ms 4700 KB Output is correct
5 Correct 1 ms 4700 KB Output is correct
6 Correct 2 ms 4548 KB Output is correct
7 Correct 2 ms 4700 KB Output is correct
8 Correct 2 ms 4696 KB Output is correct
9 Correct 2 ms 4700 KB Output is correct
10 Correct 2 ms 4700 KB Output is correct
11 Correct 2 ms 5208 KB Output is correct
12 Correct 3 ms 5316 KB Output is correct
13 Correct 3 ms 5464 KB Output is correct
14 Correct 2 ms 4956 KB Output is correct
15 Correct 337 ms 101188 KB Output is correct
16 Correct 540 ms 126228 KB Output is correct
17 Correct 779 ms 144180 KB Output is correct
18 Correct 864 ms 164944 KB Output is correct
19 Correct 747 ms 164512 KB Output is correct
20 Correct 849 ms 176292 KB Output is correct
21 Correct 80 ms 20584 KB Output is correct
22 Correct 95 ms 20060 KB Output is correct
23 Correct 106 ms 20188 KB Output is correct
24 Correct 127 ms 21540 KB Output is correct
25 Correct 163 ms 23928 KB Output is correct
26 Correct 68 ms 21840 KB Output is correct
27 Correct 90 ms 22096 KB Output is correct
28 Correct 102 ms 22352 KB Output is correct
29 Correct 161 ms 23900 KB Output is correct
30 Correct 147 ms 25508 KB Output is correct
31 Correct 94 ms 36012 KB Output is correct
32 Correct 158 ms 44744 KB Output is correct
33 Correct 182 ms 49232 KB Output is correct
34 Correct 267 ms 55316 KB Output is correct
35 Correct 216 ms 59360 KB Output is correct
36 Correct 285 ms 84488 KB Output is correct