oj.uz

Submission #653639

# Submission time Handle Problem Language Result Execution time Memory
653639 2022-10-27T13:28:49 Z pauloamed Dango Maker (JOI18_dango_maker) C++14
33 / 100
 299 ms 262144 KB 
#include<bits/stdc++.h>
using namespace std;

// Edge structure: handles node pointed to, capacity
// and the index in v[to] to its reverse edge
struct Edge{
  int to, rev;
  int cap; //
  Edge(int t, int c, int r, bool irev):to{t},rev{r},cap{c}
  {}
};
 
 
struct Flow{
  int n, s, t; // n: # nodes, s: source, t: sink
  vector<vector<Edge>> v; // extended adj list
  vector<int> lvl; // indicates the lvl for each node. used for the lvl graph
 
  // assures that each edge is completely visited only once. keeps sort of backup
  // of the index of the last visited edge
  // there is no need to revisit an edge, hence, these can be skipped
  vector<int> lastPos;
 
  // constructor
  Flow(int N, int src, int snk){
    this->n = N;
    this->s = src;
    this->t = snk;
    v = vector<vector<Edge>>(n, vector<Edge>());
  }
 
  // adding edges: endpoints and capacities
  // in case of bidirecitonal edges, use this function twice, one for each direction
  // using the full capacity on both
  void addEdge(int a, int b, int c){
    v[a].push_back({b,c,(int)v[b].size(),false});
    v[b].push_back({a,0,((int)v[a].size()) - 1,true});
  }
 
  // "builds" the lvl graph. simple bfs indicating the lvl for each node
  void getLvls(){
    queue<int> q; q.push(s);
    lvl.assign(n,-1); lvl[s] = 0;
    while(q.size()){
      int x = q.front(); q.pop();
      for(auto e : v[x]){
        if(lvl[e.to] == -1 && e.cap){
          // lvl graph only reaches new nodes and possible edges (cap > 0)
          q.push(e.to);
          lvl[e.to] = lvl[x] + 1;
        }
      }
    }
  }
 
  // finds an augmenting path and updates edges
  int dfs(int i, int curr = INT_MAX){
    if(i == t){
      return curr; // reached sink, returning collected flow
    }else{
      for(; lastPos[i] < v[i].size(); ++lastPos[i]){
        auto &e = v[i][lastPos[i]];
        if(e.cap && lvl[i] + 1 == lvl[e.to]){
          // possible edges (cap > 0) and lvl-graph structure (consecutive lvls traversal)
 
          int maybe_flow = dfs(e.to, min(curr, e.cap));
          if(maybe_flow == 0) continue;
 
          e.cap -= maybe_flow; // updating edge
          v[e.to][e.rev].cap += maybe_flow; // and its reverse
          return maybe_flow;
        }
      }
    }
    return 0;
  }
 
  // main funct
  int run(){
    int flow = 0; // initial flow
    while(true){
      getLvls(); // builds lvl graph
      // if the sink cant be reached, the max flow has been found
      if(lvl[t]==-1) break;
      // get a blocking flow for the current lvl graph
      int blocking = -1;
      lastPos.assign(n,0);
      while((blocking = dfs(s))) flow += blocking;
    }
    return flow;
  }
};

const int SRC = 0;
const int SINK = 1;
const int OFFSET = 2;


const int MAXN = 3001;
string s[MAXN];

int idv[MAXN][MAXN];
vector<pair<int,int>> es;

int main(){
  memset(idv, -1, sizeof idv);

  cin.tie(NULL)->sync_with_stdio(false);
  int n, m; cin >> n >> m;
  for(int i = 0; i < n; ++i){
    cin >> s[i];
    s[i].shrink_to_fit();
  }

  int curr_idv = 0;
  for(int i = 0; i < n; ++i){
    for(int j = 0; j < m; ++j){
      // ver
      if(i + 2 < n){
        if((s[i][j] == 'R') && (s[i+1][j] == 'G') && (s[i+2][j] == 'W')){
          idv[i][j] = curr_idv;
          idv[i+1][j] = curr_idv;
          idv[i+2][j] = curr_idv;
          curr_idv++;
        }
      }
    }
  }

  int curr_idh = 0;
  for(int i = 0; i < n; ++i){
    for(int j = 0; j < m; ++j){
      if(j + 2 < m){
        if((s[i][j] == 'R') && (s[i][j+1] == 'G') && (s[i][j+2] == 'W')){
          if(idv[i][j] != -1) es.push_back({curr_idh, idv[i][j]});
          if(idv[i][j+1] != -1) es.push_back({curr_idh, idv[i][j+1]});
          if(idv[i][j+2] != -1) es.push_back({curr_idh, idv[i][j+2]});
          curr_idh++;
        }
      }
    }
  }
  // ESQ: VERTICAIS
  // DIR: HORIZONTAIS

  Flow f(2 + curr_idh + curr_idv, SRC, SINK);
  for(int i = 0; i < curr_idv; ++i){
    f.addEdge(SRC, i + OFFSET, 1);
  }
  for(int i = 0; i < curr_idh; ++i){
    f.addEdge(i + curr_idv + OFFSET, SINK, 1);
  }

  while(es.size()){
    auto [a, b] = es.back();
    es.pop_back();
    f.addEdge(b + OFFSET, curr_idv + a + OFFSET, 1);
  }

  int x = f.run();
  // cout << x << " " << curr_idh << " " << curr_idv<< endl;
  cout << curr_idh + curr_idv - x << "\n";
}

Compilation message

dango_maker.cpp: In member function 'int Flow::dfs(int, int)':
dango_maker.cpp:61:24: warning: comparison of integer expressions of different signedness: '__gnu_cxx::__alloc_traits<std::allocator<int>, int>::value_type' {aka 'int'} and 'std::vector<Edge>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   61 |       for(; lastPos[i] < v[i].size(); ++lastPos[i]){
dango_maker.cpp: In function 'int main()':
dango_maker.cpp:155:10: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  155 |     auto [a, b] = es.back();
      |          ^

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 35540 KB Output is correct
2 Correct 18 ms 35540 KB Output is correct
3 Correct 15 ms 35588 KB Output is correct
4 Correct 15 ms 35572 KB Output is correct
5 Correct 15 ms 35540 KB Output is correct
6 Correct 17 ms 35540 KB Output is correct
7 Correct 16 ms 35540 KB Output is correct
8 Correct 16 ms 35540 KB Output is correct
9 Correct 14 ms 35648 KB Output is correct
10 Correct 15 ms 35556 KB Output is correct
11 Correct 14 ms 35592 KB Output is correct
12 Correct 17 ms 35540 KB Output is correct
13 Correct 16 ms 35620 KB Output is correct
14 Correct 15 ms 35604 KB Output is correct
15 Correct 17 ms 35540 KB Output is correct
16 Correct 15 ms 35596 KB Output is correct

Subtask #2
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 35540 KB Output is correct
2 Correct 18 ms 35540 KB Output is correct
3 Correct 15 ms 35588 KB Output is correct
4 Correct 15 ms 35572 KB Output is correct
5 Correct 15 ms 35540 KB Output is correct
6 Correct 17 ms 35540 KB Output is correct
7 Correct 16 ms 35540 KB Output is correct
8 Correct 16 ms 35540 KB Output is correct
9 Correct 14 ms 35648 KB Output is correct
10 Correct 15 ms 35556 KB Output is correct
11 Correct 14 ms 35592 KB Output is correct
12 Correct 17 ms 35540 KB Output is correct
13 Correct 16 ms 35620 KB Output is correct
14 Correct 15 ms 35604 KB Output is correct
15 Correct 17 ms 35540 KB Output is correct
16 Correct 15 ms 35596 KB Output is correct
17 Correct 14 ms 35540 KB Output is correct
18 Correct 16 ms 35632 KB Output is correct
19 Correct 15 ms 35668 KB Output is correct
20 Correct 16 ms 35592 KB Output is correct
21 Correct 16 ms 35600 KB Output is correct
22 Correct 15 ms 35668 KB Output is correct
23 Correct 16 ms 35668 KB Output is correct
24 Correct 15 ms 35624 KB Output is correct
25 Correct 15 ms 35540 KB Output is correct
26 Correct 16 ms 35540 KB Output is correct
27 Correct 15 ms 35592 KB Output is correct
28 Correct 17 ms 35668 KB Output is correct
29 Correct 15 ms 35608 KB Output is correct
30 Correct 15 ms 35560 KB Output is correct
31 Correct 17 ms 35668 KB Output is correct
32 Correct 15 ms 35588 KB Output is correct
33 Correct 15 ms 35668 KB Output is correct
34 Correct 16 ms 35568 KB Output is correct
35 Correct 14 ms 35656 KB Output is correct
36 Correct 14 ms 35668 KB Output is correct
37 Correct 15 ms 35592 KB Output is correct
38 Correct 16 ms 35556 KB Output is correct
39 Correct 15 ms 35624 KB Output is correct
40 Correct 15 ms 35668 KB Output is correct
41 Correct 16 ms 35668 KB Output is correct
42 Correct 15 ms 35612 KB Output is correct
43 Correct 16 ms 35668 KB Output is correct
44 Correct 15 ms 35668 KB Output is correct
45 Correct 15 ms 35668 KB Output is correct
46 Correct 15 ms 35668 KB Output is correct
47 Correct 15 ms 35668 KB Output is correct
48 Correct 15 ms 35608 KB Output is correct
49 Correct 15 ms 35668 KB Output is correct
50 Correct 15 ms 35668 KB Output is correct
51 Correct 16 ms 35584 KB Output is correct
52 Correct 17 ms 35644 KB Output is correct
53 Correct 15 ms 35668 KB Output is correct

Subtask #3
0 / 67.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 35540 KB Output is correct
2 Correct 18 ms 35540 KB Output is correct
3 Correct 15 ms 35588 KB Output is correct
4 Correct 15 ms 35572 KB Output is correct
5 Correct 15 ms 35540 KB Output is correct
6 Correct 17 ms 35540 KB Output is correct
7 Correct 16 ms 35540 KB Output is correct
8 Correct 16 ms 35540 KB Output is correct
9 Correct 14 ms 35648 KB Output is correct
10 Correct 15 ms 35556 KB Output is correct
11 Correct 14 ms 35592 KB Output is correct
12 Correct 17 ms 35540 KB Output is correct
13 Correct 16 ms 35620 KB Output is correct
14 Correct 15 ms 35604 KB Output is correct
15 Correct 17 ms 35540 KB Output is correct
16 Correct 15 ms 35596 KB Output is correct
17 Correct 14 ms 35540 KB Output is correct
18 Correct 16 ms 35632 KB Output is correct
19 Correct 15 ms 35668 KB Output is correct
20 Correct 16 ms 35592 KB Output is correct
21 Correct 16 ms 35600 KB Output is correct
22 Correct 15 ms 35668 KB Output is correct
23 Correct 16 ms 35668 KB Output is correct
24 Correct 15 ms 35624 KB Output is correct
25 Correct 15 ms 35540 KB Output is correct
26 Correct 16 ms 35540 KB Output is correct
27 Correct 15 ms 35592 KB Output is correct
28 Correct 17 ms 35668 KB Output is correct
29 Correct 15 ms 35608 KB Output is correct
30 Correct 15 ms 35560 KB Output is correct
31 Correct 17 ms 35668 KB Output is correct
32 Correct 15 ms 35588 KB Output is correct
33 Correct 15 ms 35668 KB Output is correct
34 Correct 16 ms 35568 KB Output is correct
35 Correct 14 ms 35656 KB Output is correct
36 Correct 14 ms 35668 KB Output is correct
37 Correct 15 ms 35592 KB Output is correct
38 Correct 16 ms 35556 KB Output is correct
39 Correct 15 ms 35624 KB Output is correct
40 Correct 15 ms 35668 KB Output is correct
41 Correct 16 ms 35668 KB Output is correct
42 Correct 15 ms 35612 KB Output is correct
43 Correct 16 ms 35668 KB Output is correct
44 Correct 15 ms 35668 KB Output is correct
45 Correct 15 ms 35668 KB Output is correct
46 Correct 15 ms 35668 KB Output is correct
47 Correct 15 ms 35668 KB Output is correct
48 Correct 15 ms 35608 KB Output is correct
49 Correct 15 ms 35668 KB Output is correct
50 Correct 15 ms 35668 KB Output is correct
51 Correct 16 ms 35584 KB Output is correct
52 Correct 17 ms 35644 KB Output is correct
53 Correct 15 ms 35668 KB Output is correct
54 Correct 15 ms 35584 KB Output is correct
55 Correct 15 ms 35668 KB Output is correct
56 Correct 15 ms 35924 KB Output is correct
57 Correct 17 ms 35868 KB Output is correct
58 Correct 44 ms 43264 KB Output is correct
59 Correct 299 ms 98564 KB Output is correct
60 Correct 296 ms 98420 KB Output is correct
61 Correct 291 ms 98260 KB Output is correct
62 Correct 15 ms 35668 KB Output is correct
63 Correct 289 ms 96380 KB Output is correct
64 Runtime error 262 ms 262144 KB Execution killed with signal 9
65 Halted 0 ms 0 KB -