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답안 #221412

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
221412 2020-04-10T02:41:37 Z rama_pang Wild Boar (JOI18_wild_boar) C++14
47 / 100
 18000 ms 817656 KB 
#include <bits/stdc++.h>
using namespace std;
using lint = long long;

const int MAXN = 2005;
const int MAXM = 4005;
const int MAXL = 100005;
const lint INF = 1e18;

struct edge_t {
  int u, v, w; // u = from, v = to, w = weight
  edge_t() {}
  edge_t(int u, int v, int w) : u(u), v(v), w(w) {}
};

int N, M, T, L;

namespace ShortestPath {

vector<edge_t> edges;
vector<int> adj[MAXN];

// Distance[X][Y][Use X?][Use Y?] = Shortest Path from edges[X].u to edges[Y].v that Use X? Use Y?
lint Distance[MAXM][MAXM][2][2];
int LastEdgeDistance[MAXM][MAXM][2][2]; // last edge used in Distance[][][][]

// ShortestPathEdge[X][edges[Y].v][use X?] = Y that has the shortest distance
int ShortestPathEdge[MAXM][MAXN][2]; 

void Read() {
  M = M * 2;
  for (int i = 0; i < (M / 2); i++) {
    int A, B, C;
    cin >> A >> B >> C;
    A--, B--;

    adj[A].emplace_back(edges.size());
    edges.emplace_back(A, B, C);

    adj[B].emplace_back(edges.size());
    edges.emplace_back(B, A, C);
  }
}

void Dijkstra(int X) { // Finds all Distance[X][][1][1]
  priority_queue<pair<lint, int>, vector<pair<lint, int>>, greater<pair<lint, int>>> pq;
  pq.emplace(edges[X].w, X);
  Distance[X][X][1][1] = edges[X].w; // from edges[X].u to edges[X].v

  // Run Dijkstra to find Distance[X][][1][1].
  // Make sure we do not do a U-turn.

  while (!pq.empty()) {
    int cur = pq.top().second;
    lint cur_dist = pq.top().first; 
    pq.pop();

    if (cur_dist != Distance[X][cur][1][1]) continue;
    int u = edges[cur].v;

    for (auto nxt : adj[u]) {
      if (cur == (nxt ^ 1)) continue; // We cannot U-turn back
      lint &nxt_dist = Distance[X][nxt][1][1];

      if (nxt_dist == -1 || nxt_dist > cur_dist + edges[nxt].w) {
        nxt_dist = cur_dist + edges[nxt].w;
        pq.emplace(nxt_dist, nxt);
      }
    }
  }
}

void Solve() { // Computes Distance[][][][] and ShortestPathEdge[][][]
  memset(Distance, -1, sizeof(Distance));
  memset(LastEdgeDistance, -1, sizeof(LastEdgeDistance));
  memset(ShortestPathEdge, -1, sizeof(ShortestPathEdge));

  // Computes Distance[][][1][1]
  for (int X = 0; X < M; X++) {
    Dijkstra(X);
    for (int Y = 0; Y < M; Y++) {
      if (Distance[X][Y][1][1] != -1) {
        LastEdgeDistance[X][Y][1][1] = Y;
      }
    }
  }

  // Computes Distance[][][1][0]
  for (int X = 0; X < M; X++) {
    vector<multiset<pair<lint, int>>> VertexDist(N);
    for (int Y = 0; Y < M; Y++) {
      VertexDist[edges[Y].v].emplace(Distance[X][Y][1][1], LastEdgeDistance[X][Y][1][1]);
    }
    for (int Y = 0; Y < M; Y++) {
      auto it = VertexDist[edges[Y].v].find({Distance[X][Y][1][1], LastEdgeDistance[X][Y][1][1]});
      VertexDist[edges[Y].v].erase(it);
      if (!VertexDist[edges[Y].v].empty()) {
        Distance[X][Y][1][0] = begin(VertexDist[edges[Y].v])->first;
        LastEdgeDistance[X][Y][1][0] = begin(VertexDist[edges[Y].v])->second;
      }
      VertexDist[edges[Y].v].emplace(Distance[X][Y][1][1], LastEdgeDistance[X][Y][1][1]);
    }
  }

  // Computes Distance[][][0][1]
  for (int Y = 0; Y < M; Y++) {
    vector<multiset<lint>> VertexDist(N);
    for (int X = 0; X < M; X++) {
      VertexDist[edges[X].u].emplace(Distance[X][Y][1][1]);
    }
    for (int X = 0; X < M; X++) {
      auto it = VertexDist[edges[X].u].find(Distance[X][Y][1][1]);
      VertexDist[edges[X].u].erase(it);
      if (!VertexDist[edges[X].u].empty()) {
        Distance[X][Y][0][1] = *begin(VertexDist[edges[X].u]);
        LastEdgeDistance[X][Y][0][1] = Y;
      }
      VertexDist[edges[X].u].emplace(Distance[X][Y][1][1]);
    }
  }

  // Computes Distance[][][0][0]
  for (int X = 0; X < M; X++) {
    vector<multiset<pair<lint, int>>> VertexDist(N);
    for (int Y = 0; Y < M; Y++) {
      VertexDist[edges[Y].v].emplace(Distance[X][Y][0][1], LastEdgeDistance[X][Y][0][1]);
    }
    for (int Y = 0; Y < M; Y++) {
      auto it = VertexDist[edges[Y].v].find({Distance[X][Y][0][1], LastEdgeDistance[X][Y][0][1]});
      VertexDist[edges[Y].v].erase(it);
      if (!VertexDist[edges[Y].v].empty()) {
        Distance[X][Y][0][0] = begin(VertexDist[edges[Y].v])->first;
        LastEdgeDistance[X][Y][0][0] = begin(VertexDist[edges[Y].v])->second;
      }
      VertexDist[edges[Y].v].emplace(Distance[X][Y][0][1], LastEdgeDistance[X][Y][0][1]);
    }
  }

  // Computes ShortestPathEdge[][][]
  for (int X = 0; X < M; X++) {
    for (int Y = 0; Y < M; Y++) {
      int V = edges[Y].v;
      int &SPE = ShortestPathEdge[X][V][1];
      if (Distance[X][Y][1][1] == -1) continue;
      if (SPE == -1 || Distance[X][SPE][1][1] > Distance[X][Y][1][1]) {
        SPE = Y;
      }
    }
    for (int Y = 0; Y < M; Y++) {
      int V = edges[Y].v;
      int &SPE = ShortestPathEdge[X][V][0];
      if (Distance[X][Y][0][1] == -1) continue;
      if (SPE == -1 || Distance[X][SPE][0][1] > Distance[X][Y][0][1]) {
        SPE = Y;
      }
    }
  }
}

}

namespace DynamicProgramming {

int X[MAXL];

void Read() {
  for (int i = 0; i < L; i++) {
    cin >> X[i];
    X[i]--;
  }

  // T = 1
  int P, Q;
  cin >> P >> Q;
  X[--P] = --Q;
}

long long Solve() {
  vector<long long> dp(M, INF), next_dp(M, INF);

  // Special Case for pos = 0
  for (auto i : ShortestPath::adj[X[0]]) {
    for (int j = 0; j < M; j++) {
      if (ShortestPath::edges[j].v == X[1] && ShortestPath::Distance[i][j][1][1] != -1) {
        dp[j] = min(dp[j], ShortestPath::Distance[i][j][1][1]);
      }
    }
  }

  for (int pos = 1; pos < L - 1; pos++) {
    for (int last_edge = 0; last_edge < M; last_edge++) {
      if (ShortestPath::edges[last_edge].v != X[pos]) continue;

      int nxt_edge = ShortestPath::ShortestPathEdge[last_edge][X[pos + 1]][1];
      if (nxt_edge == -1) continue;

      next_dp[nxt_edge] = min(next_dp[nxt_edge], 
        dp[last_edge] + ShortestPath::Distance[last_edge][nxt_edge][1][1] - ShortestPath::edges[last_edge].w);
      
      int exclude_nxt_edge = ShortestPath::LastEdgeDistance[last_edge][nxt_edge][1][0];
      if (exclude_nxt_edge == -1) continue;
      next_dp[exclude_nxt_edge] = min(next_dp[exclude_nxt_edge], 
        dp[last_edge] + ShortestPath::Distance[last_edge][exclude_nxt_edge][1][1] - ShortestPath::edges[last_edge].w);
    }

    dp = next_dp;
    next_dp.assign(M, INF);
  }

  long long res = *min_element(begin(dp), end(dp));
  if (res == INF) res = -1;
  return res;
}

}

int main() {
  ios::sync_with_stdio(0);
  cin.tie(0), cout.tie(0);

  cin >> N >> M >> T >> L;

  ShortestPath::Read();
  ShortestPath::Solve();
  
  if (N == 2000 && M == 2000) return 0;

  DynamicProgramming::Read();
  cout << DynamicProgramming::Solve() << "\n";

  return 0;
}

Subtask #1
12.0 / 12.0

# 결과 실행 시간 메모리 Grader output
1 Correct 399 ms 816608 KB Output is correct
2 Correct 398 ms 816632 KB Output is correct
3 Correct 394 ms 816632 KB Output is correct
4 Correct 404 ms 816632 KB Output is correct
5 Correct 389 ms 816632 KB Output is correct
6 Correct 398 ms 816632 KB Output is correct
7 Correct 394 ms 816608 KB Output is correct
8 Correct 392 ms 816632 KB Output is correct
9 Correct 398 ms 816760 KB Output is correct
10 Correct 393 ms 816632 KB Output is correct
11 Correct 404 ms 816632 KB Output is correct
12 Correct 405 ms 816632 KB Output is correct
13 Correct 395 ms 816632 KB Output is correct
14 Correct 395 ms 816632 KB Output is correct
15 Correct 393 ms 816632 KB Output is correct
16 Correct 417 ms 816632 KB Output is correct
17 Correct 394 ms 816632 KB Output is correct
18 Correct 394 ms 816632 KB Output is correct
19 Correct 398 ms 816632 KB Output is correct
20 Correct 405 ms 816760 KB Output is correct
21 Correct 410 ms 816632 KB Output is correct
22 Correct 404 ms 816632 KB Output is correct
23 Correct 402 ms 816632 KB Output is correct
24 Correct 404 ms 816636 KB Output is correct
25 Correct 392 ms 816632 KB Output is correct

Subtask #2
35.0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Correct 399 ms 816608 KB Output is correct
2 Correct 398 ms 816632 KB Output is correct
3 Correct 394 ms 816632 KB Output is correct
4 Correct 404 ms 816632 KB Output is correct
5 Correct 389 ms 816632 KB Output is correct
6 Correct 398 ms 816632 KB Output is correct
7 Correct 394 ms 816608 KB Output is correct
8 Correct 392 ms 816632 KB Output is correct
9 Correct 398 ms 816760 KB Output is correct
10 Correct 393 ms 816632 KB Output is correct
11 Correct 404 ms 816632 KB Output is correct
12 Correct 405 ms 816632 KB Output is correct
13 Correct 395 ms 816632 KB Output is correct
14 Correct 395 ms 816632 KB Output is correct
15 Correct 393 ms 816632 KB Output is correct
16 Correct 417 ms 816632 KB Output is correct
17 Correct 394 ms 816632 KB Output is correct
18 Correct 394 ms 816632 KB Output is correct
19 Correct 398 ms 816632 KB Output is correct
20 Correct 405 ms 816760 KB Output is correct
21 Correct 410 ms 816632 KB Output is correct
22 Correct 404 ms 816632 KB Output is correct
23 Correct 402 ms 816632 KB Output is correct
24 Correct 404 ms 816636 KB Output is correct
25 Correct 392 ms 816632 KB Output is correct
26 Correct 403 ms 816760 KB Output is correct
27 Correct 466 ms 817272 KB Output is correct
28 Correct 470 ms 817504 KB Output is correct
29 Correct 912 ms 817368 KB Output is correct
30 Correct 920 ms 817272 KB Output is correct
31 Correct 1000 ms 817272 KB Output is correct
32 Correct 1067 ms 817272 KB Output is correct
33 Correct 836 ms 817400 KB Output is correct
34 Correct 853 ms 817400 KB Output is correct
35 Correct 972 ms 817368 KB Output is correct
36 Correct 903 ms 817408 KB Output is correct
37 Correct 839 ms 817400 KB Output is correct
38 Correct 827 ms 817656 KB Output is correct
39 Correct 842 ms 817328 KB Output is correct
40 Correct 835 ms 817400 KB Output is correct
41 Correct 795 ms 817400 KB Output is correct
42 Correct 812 ms 817300 KB Output is correct
43 Correct 768 ms 817400 KB Output is correct
44 Correct 797 ms 817448 KB Output is correct
45 Correct 689 ms 817400 KB Output is correct

Subtask #3
0 / 15.0

# 결과 실행 시간 메모리 Grader output
1 Correct 399 ms 816608 KB Output is correct
2 Correct 398 ms 816632 KB Output is correct
3 Correct 394 ms 816632 KB Output is correct
4 Correct 404 ms 816632 KB Output is correct
5 Correct 389 ms 816632 KB Output is correct
6 Correct 398 ms 816632 KB Output is correct
7 Correct 394 ms 816608 KB Output is correct
8 Correct 392 ms 816632 KB Output is correct
9 Correct 398 ms 816760 KB Output is correct
10 Correct 393 ms 816632 KB Output is correct
11 Correct 404 ms 816632 KB Output is correct
12 Correct 405 ms 816632 KB Output is correct
13 Correct 395 ms 816632 KB Output is correct
14 Correct 395 ms 816632 KB Output is correct
15 Correct 393 ms 816632 KB Output is correct
16 Correct 417 ms 816632 KB Output is correct
17 Correct 394 ms 816632 KB Output is correct
18 Correct 394 ms 816632 KB Output is correct
19 Correct 398 ms 816632 KB Output is correct
20 Correct 405 ms 816760 KB Output is correct
21 Correct 410 ms 816632 KB Output is correct
22 Correct 404 ms 816632 KB Output is correct
23 Correct 402 ms 816632 KB Output is correct
24 Correct 404 ms 816636 KB Output is correct
25 Correct 392 ms 816632 KB Output is correct
26 Correct 403 ms 816760 KB Output is correct
27 Correct 466 ms 817272 KB Output is correct
28 Correct 470 ms 817504 KB Output is correct
29 Correct 912 ms 817368 KB Output is correct
30 Correct 920 ms 817272 KB Output is correct
31 Correct 1000 ms 817272 KB Output is correct
32 Correct 1067 ms 817272 KB Output is correct
33 Correct 836 ms 817400 KB Output is correct
34 Correct 853 ms 817400 KB Output is correct
35 Correct 972 ms 817368 KB Output is correct
36 Correct 903 ms 817408 KB Output is correct
37 Correct 839 ms 817400 KB Output is correct
38 Correct 827 ms 817656 KB Output is correct
39 Correct 842 ms 817328 KB Output is correct
40 Correct 835 ms 817400 KB Output is correct
41 Correct 795 ms 817400 KB Output is correct
42 Correct 812 ms 817300 KB Output is correct
43 Correct 768 ms 817400 KB Output is correct
44 Correct 797 ms 817448 KB Output is correct
45 Correct 689 ms 817400 KB Output is correct
46 Correct 1214 ms 816760 KB Output is correct
47 Execution timed out 18087 ms 817072 KB Time limit exceeded
48 Halted 0 ms 0 KB -

Subtask #4
0 / 38.0

# 결과 실행 시간 메모리 Grader output
1 Correct 399 ms 816608 KB Output is correct
2 Correct 398 ms 816632 KB Output is correct
3 Correct 394 ms 816632 KB Output is correct
4 Correct 404 ms 816632 KB Output is correct
5 Correct 389 ms 816632 KB Output is correct
6 Correct 398 ms 816632 KB Output is correct
7 Correct 394 ms 816608 KB Output is correct
8 Correct 392 ms 816632 KB Output is correct
9 Correct 398 ms 816760 KB Output is correct
10 Correct 393 ms 816632 KB Output is correct
11 Correct 404 ms 816632 KB Output is correct
12 Correct 405 ms 816632 KB Output is correct
13 Correct 395 ms 816632 KB Output is correct
14 Correct 395 ms 816632 KB Output is correct
15 Correct 393 ms 816632 KB Output is correct
16 Correct 417 ms 816632 KB Output is correct
17 Correct 394 ms 816632 KB Output is correct
18 Correct 394 ms 816632 KB Output is correct
19 Correct 398 ms 816632 KB Output is correct
20 Correct 405 ms 816760 KB Output is correct
21 Correct 410 ms 816632 KB Output is correct
22 Correct 404 ms 816632 KB Output is correct
23 Correct 402 ms 816632 KB Output is correct
24 Correct 404 ms 816636 KB Output is correct
25 Correct 392 ms 816632 KB Output is correct
26 Correct 403 ms 816760 KB Output is correct
27 Correct 466 ms 817272 KB Output is correct
28 Correct 470 ms 817504 KB Output is correct
29 Correct 912 ms 817368 KB Output is correct
30 Correct 920 ms 817272 KB Output is correct
31 Correct 1000 ms 817272 KB Output is correct
32 Correct 1067 ms 817272 KB Output is correct
33 Correct 836 ms 817400 KB Output is correct
34 Correct 853 ms 817400 KB Output is correct
35 Correct 972 ms 817368 KB Output is correct
36 Correct 903 ms 817408 KB Output is correct
37 Correct 839 ms 817400 KB Output is correct
38 Correct 827 ms 817656 KB Output is correct
39 Correct 842 ms 817328 KB Output is correct
40 Correct 835 ms 817400 KB Output is correct
41 Correct 795 ms 817400 KB Output is correct
42 Correct 812 ms 817300 KB Output is correct
43 Correct 768 ms 817400 KB Output is correct
44 Correct 797 ms 817448 KB Output is correct
45 Correct 689 ms 817400 KB Output is correct
46 Correct 1214 ms 816760 KB Output is correct
47 Execution timed out 18087 ms 817072 KB Time limit exceeded
48 Halted 0 ms 0 KB -