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Submission #632020

# Submission time Handle Problem Language Result Execution time Memory
632020 2022-08-19T10:13:22 Z CyanForces Thousands Islands (IOI22_islands) C++17
100 / 100
 317 ms 36276 KB 
#include "islands.h"

#include <bits/stdc++.h>
using namespace std;

#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
#define debug(...) //ignore
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
typedef long double ld;

variant<bool, vi> find_journey(int n, int m, vi u, vi v) {
  vi dead(n);
  vector<set<int>> rg(n), g(n);
  rep(i,0,m) {
    g[u[i]].emplace(i);
    rg[v[i]].emplace(i);
  }

  queue<int> q;
  rep(x,0,n) if(sz(g[x]) == 0) q.emplace(x);

  auto del = [&](int e) {
    g[u[e]].erase(e);
    rg[v[e]].erase(e);
    if(sz(g[u[e]]) == 0) q.emplace(u[e]);
  };

  auto trim = [&]() {
    while(sz(q)) {
      int x = q.front();
      q.pop();
      dead[x] = true;
      vi es(all(rg[x]));
      for(int e : es) del(e);
    }
  };

  trim();
  if(dead[0]) return false;

  vi pth0;
  int x = 0;
  int lst_e = -1;
  while(sz(g[x]) == 1) {
    assert(!dead[x]);
    int e = *g[x].begin();
    pth0.emplace_back(e);

    vi es(all(rg[x]));
    for(int e : es) if(e != lst_e) del(e);
    trim();
    if(dead[0]) return false;

    x = v[e];
    lst_e = e;
  }
  assert(!dead[x]);
  assert(sz(g[x]) >= 2);

  debug(x);
  debug(g[x]);

  vi vis(n);
  vis[x] = 3;
  vi pth1, pth2;

  {
    int e = *g[x].begin();
    pth1.emplace_back(e);
    while(!vis[v[e]]) {
      vis[v[e]] = 1;
      e = *g[v[e]].begin();
      pth1.emplace_back(e);
    }
  }

  {
    int e = *g[x].rbegin();
    pth2.emplace_back(e);
    while(!vis[v[e]]) {
      vis[v[e]] = 2;
      e = *g[v[e]].begin();
      pth2.emplace_back(e);
    }
  }

  debug(pth0, pth1, pth2);
  vi important(n);
  important[x] = 1;
  important[v[pth1.back()]] = 1;
  important[v[pth2.back()]] = 1;

  vector<vi> s1, s2;
  vi cur;
  for(int a : pth1) {
    cur.emplace_back(a);
    if(important[v[a]]) {
      s1.emplace_back(cur);
      cur.clear();
    }
  }

  cur.clear();
  for(int a : pth2) {
    cur.emplace_back(a);
    if(important[v[a]]) {
      s2.emplace_back(cur);
      cur.clear();
    }
  }

  debug(s1);
  debug(s2);

  auto rev = [&](vi v) {
    reverse(all(v));
    return v;
  };

  auto flatten = [&](vector<vi> ve) {
    vi res;
    for(auto& es : ve) for(int e : es) res.emplace_back(e);
    return res;
  };
  auto go = [&](vector<vi> ve) {
    ve.insert(begin(ve),pth0);
    ve.emplace_back(rev(pth0));
    int x = 0;
    vi res = flatten(ve);
    int lst_e = -1;
    for(int e : res) {
      assert(x == u[e]);
      assert(e != lst_e);
      lst_e = e;
      x = v[e];
      swap(u[e], v[e]);
    }
    return res;
  };

  auto do_cyc = [&](vector<vi> s, bool r) {
    vector<vi> g;
    if(sz(s) == 1) g.emplace_back(r ? rev(s[0]) : s[0]);
    else if(sz(s) == 2) {
      g.emplace_back(s[0]);
      g.emplace_back(r ? rev(s[1]) : s[1]);
      g.emplace_back(rev(s[0]));
    }
    else assert(false);
    return flatten(g);
  };

  if(vis[v[s2.back().back()]] != 1) { // separate
    vector<vi> g;
    g.emplace_back(do_cyc(s1,false));
    g.emplace_back(do_cyc(s2,false));
    g.emplace_back(do_cyc(s1,true));
    g.emplace_back(do_cyc(s2,true));
    debug(g);
    return go(g);
  }

  assert(sz(s2) == 1);

  if(v[s1[0].back()] == v[s2[0].back()]) {

    vector<vi> g;

    if(v[s1.back().back()] == x) {
      assert(sz(s1) == 2);
      g.emplace_back(s1[0]);
      g.emplace_back(s1[1]);
      g.emplace_back(s2[0]);
      g.emplace_back(rev(s1[0]));
      g.emplace_back(rev(s1[1]));
      g.emplace_back(rev(s2[0]));
      return go(g);
    }

    auto ss1 = s1;
    ss1.erase(begin(ss1));

    g.emplace_back(s1[0]);
    g.emplace_back(do_cyc(ss1,false));
    g.emplace_back(rev(s1[0]));
    g.emplace_back(s2[0]);
    g.emplace_back(do_cyc(ss1,true));
    g.emplace_back(rev(s2[0]));
    return go(g);
  }


  if(v[s1[1].back()] == v[s2[0].back()]) {
    assert(sz(s1) == 3);
    vector<vi> g;
    g.emplace_back(s1[0]);
    g.emplace_back(s1[1]);
    g.emplace_back(s1[2]);
    g.emplace_back(rev(s1[0]));
    g.emplace_back(s2[0]);
    g.emplace_back(rev(s1[1]));
    g.emplace_back(rev(s1[2]));
    g.emplace_back(rev(s2[0]));
    return go(g);
  }


  return true;

  assert(false);

  return true;
}

Subtask #1
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 300 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 115 ms 22188 KB Output is correct

Subtask #2
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 147 ms 17804 KB Output is correct

Subtask #3
21.0 / 21.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 724 KB Output is correct
2 Correct 1 ms 212 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 240 KB Output is correct
5 Correct 2 ms 596 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 468 KB Output is correct
8 Correct 1 ms 212 KB Output is correct
9 Correct 1 ms 212 KB Output is correct
10 Correct 1 ms 596 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 1 ms 596 KB Output is correct
13 Correct 0 ms 212 KB Output is correct
14 Correct 1 ms 212 KB Output is correct
15 Correct 0 ms 212 KB Output is correct
16 Correct 1 ms 212 KB Output is correct
17 Correct 75 ms 11240 KB Output is correct
18 Correct 52 ms 9112 KB Output is correct
19 Correct 0 ms 212 KB Output is correct
20 Correct 0 ms 212 KB Output is correct
21 Correct 0 ms 212 KB Output is correct
22 Correct 1 ms 212 KB Output is correct
23 Correct 148 ms 17808 KB Output is correct

Subtask #4
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 3 ms 724 KB Output is correct
3 Correct 190 ms 20048 KB Output is correct
4 Correct 180 ms 20316 KB Output is correct
5 Correct 2 ms 724 KB Output is correct
6 Correct 2 ms 724 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 1 ms 724 KB Output is correct
11 Correct 2 ms 724 KB Output is correct
12 Correct 2 ms 724 KB Output is correct
13 Correct 2 ms 852 KB Output is correct
14 Correct 2 ms 724 KB Output is correct
15 Correct 3 ms 980 KB Output is correct
16 Correct 1 ms 596 KB Output is correct
17 Correct 1 ms 212 KB Output is correct
18 Correct 2 ms 724 KB Output is correct
19 Correct 1 ms 596 KB Output is correct
20 Correct 205 ms 22220 KB Output is correct
21 Correct 211 ms 20144 KB Output is correct
22 Correct 1 ms 596 KB Output is correct
23 Correct 1 ms 468 KB Output is correct
24 Correct 0 ms 212 KB Output is correct
25 Correct 1 ms 468 KB Output is correct
26 Correct 1 ms 596 KB Output is correct
27 Correct 204 ms 21164 KB Output is correct
28 Correct 195 ms 21148 KB Output is correct
29 Correct 0 ms 212 KB Output is correct
30 Correct 228 ms 22216 KB Output is correct
31 Correct 0 ms 212 KB Output is correct
32 Correct 175 ms 20216 KB Output is correct
33 Correct 200 ms 21068 KB Output is correct
34 Correct 66 ms 11264 KB Output is correct
35 Correct 1 ms 468 KB Output is correct
36 Correct 154 ms 17944 KB Output is correct
37 Correct 166 ms 21240 KB Output is correct
38 Correct 2 ms 468 KB Output is correct
39 Correct 162 ms 17124 KB Output is correct
40 Correct 1 ms 596 KB Output is correct
41 Correct 210 ms 22344 KB Output is correct
42 Correct 184 ms 21120 KB Output is correct
43 Correct 1 ms 212 KB Output is correct
44 Correct 2 ms 724 KB Output is correct
45 Correct 2 ms 724 KB Output is correct
46 Correct 48 ms 9172 KB Output is correct

Subtask #5
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 212 KB Output is correct
2 Correct 0 ms 300 KB Output is correct
3 Correct 0 ms 212 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 1 ms 212 KB Output is correct
7 Correct 115 ms 22188 KB Output is correct
8 Correct 0 ms 212 KB Output is correct
9 Correct 0 ms 212 KB Output is correct
10 Correct 0 ms 212 KB Output is correct
11 Correct 0 ms 212 KB Output is correct
12 Correct 0 ms 212 KB Output is correct
13 Correct 147 ms 17804 KB Output is correct
14 Correct 2 ms 724 KB Output is correct
15 Correct 1 ms 212 KB Output is correct
16 Correct 0 ms 212 KB Output is correct
17 Correct 0 ms 240 KB Output is correct
18 Correct 2 ms 596 KB Output is correct
19 Correct 0 ms 212 KB Output is correct
20 Correct 1 ms 468 KB Output is correct
21 Correct 1 ms 212 KB Output is correct
22 Correct 1 ms 212 KB Output is correct
23 Correct 1 ms 596 KB Output is correct
24 Correct 0 ms 212 KB Output is correct
25 Correct 1 ms 596 KB Output is correct
26 Correct 0 ms 212 KB Output is correct
27 Correct 1 ms 212 KB Output is correct
28 Correct 0 ms 212 KB Output is correct
29 Correct 1 ms 212 KB Output is correct
30 Correct 75 ms 11240 KB Output is correct
31 Correct 52 ms 9112 KB Output is correct
32 Correct 0 ms 212 KB Output is correct
33 Correct 0 ms 212 KB Output is correct
34 Correct 0 ms 212 KB Output is correct
35 Correct 1 ms 212 KB Output is correct
36 Correct 148 ms 17808 KB Output is correct
37 Correct 0 ms 212 KB Output is correct
38 Correct 0 ms 212 KB Output is correct
39 Correct 1 ms 212 KB Output is correct
40 Correct 1 ms 340 KB Output is correct
41 Correct 93 ms 10172 KB Output is correct
42 Correct 3 ms 852 KB Output is correct
43 Correct 97 ms 16144 KB Output is correct
44 Correct 92 ms 16044 KB Output is correct
45 Correct 103 ms 16104 KB Output is correct
46 Correct 0 ms 212 KB Output is correct
47 Correct 1 ms 212 KB Output is correct
48 Correct 0 ms 212 KB Output is correct
49 Correct 1 ms 596 KB Output is correct
50 Correct 129 ms 28604 KB Output is correct
51 Correct 224 ms 31900 KB Output is correct
52 Correct 223 ms 32076 KB Output is correct
53 Correct 228 ms 31988 KB Output is correct
54 Correct 236 ms 32124 KB Output is correct
55 Correct 224 ms 32052 KB Output is correct
56 Correct 238 ms 32108 KB Output is correct
57 Correct 162 ms 28492 KB Output is correct
58 Correct 129 ms 28084 KB Output is correct
59 Correct 267 ms 32132 KB Output is correct
60 Correct 255 ms 32072 KB Output is correct
61 Correct 247 ms 32064 KB Output is correct
62 Correct 23 ms 8224 KB Output is correct
63 Correct 200 ms 30852 KB Output is correct
64 Correct 110 ms 11456 KB Output is correct
65 Correct 0 ms 212 KB Output is correct
66 Correct 1 ms 340 KB Output is correct
67 Correct 224 ms 32772 KB Output is correct
68 Correct 307 ms 22332 KB Output is correct
69 Correct 106 ms 21112 KB Output is correct
70 Correct 2 ms 596 KB Output is correct
71 Correct 188 ms 21652 KB Output is correct
72 Correct 0 ms 212 KB Output is correct
73 Correct 252 ms 29140 KB Output is correct
74 Correct 122 ms 26932 KB Output is correct
75 Correct 6 ms 1596 KB Output is correct
76 Correct 51 ms 13100 KB Output is correct
77 Correct 101 ms 21032 KB Output is correct
78 Correct 261 ms 32148 KB Output is correct
79 Correct 0 ms 212 KB Output is correct
80 Correct 317 ms 36276 KB Output is correct
81 Correct 1 ms 596 KB Output is correct
82 Correct 214 ms 22372 KB Output is correct
83 Correct 1 ms 468 KB Output is correct
84 Correct 0 ms 212 KB Output is correct
85 Correct 51 ms 13320 KB Output is correct
86 Correct 2 ms 724 KB Output is correct
87 Correct 6 ms 8532 KB Output is correct
88 Correct 4 ms 980 KB Output is correct
89 Correct 289 ms 32152 KB Output is correct
90 Correct 245 ms 32076 KB Output is correct
91 Correct 281 ms 35144 KB Output is correct
92 Correct 0 ms 212 KB Output is correct