oj.uz

Submission #66469

# Submission time Handle Problem Language Result Execution time Memory
66469 2018-08-10T16:21:05 Z aquablitz11 Parachute rings (IOI12_rings) C++14
100 / 100
 1361 ms 100400 KB 
#include <bits/stdc++.h>
using namespace std;
using pii = pair<int, int>;
const int N = 1e6+10;
 
// graph data
 
int n;
vector<pii> E, ES;
vector<int> G[N];
 
int dfs(int u, int p, int s, int t)
{
    if (u == t)
        return 1;
    for (auto v : G[u]) if (v != p && (u != s || v != t)) {
        int r = dfs(v, u, s, t);
        if (r) return r+1;
    }
    return 0;
}
 
// dsu with copying for experimentation
 
bool ffc = true;
int par[N], mfcnt, firstcycle;
int root(int u) {
    if (par[u] == u) return u;
    return par[u] = root(par[u]);
}
inline bool merge(int u, int v) {
    //fprintf(stderr, "merge(%d, %d)\n", u, v);
    int u0 = u, v0 = v;
    u = root(u), v = root(v);
    if (u == v) {
        if (++mfcnt == 1 && ffc)
            firstcycle = dfs(u0, -1, u0, v0);
        return false;
    }
    par[u] = v;
    return true;
}
int _np[N], _nv[N], tick;
inline int &np(int u) {
    if (_nv[u] != tick) {
        _np[u] = par[u];
        _nv[u] = tick;
    }
    return _np[u];
}
int nroot(int u) {
    if (np(u) == u) return u;
    return np(u) = nroot(np(u));
}
inline bool nmerge(int u, int v) {
    //fprintf(stderr, "nmerge(%d, %d)\n", u, v);
    u = nroot(u), v = nroot(v);
    if (u == v) return false;
    np(u) = v;
    return true;
}
 
// state control (degree freq. histogram)
 
int cntok, cnt3, cnt4, deg[N];
pii mxdeg(0, -1);
 
inline void testmod(int a, int b) {
    if (a <= 2) --cntok;
    if (a == 3) --cnt3;
    if (a >= 4) --cnt4;
    if (b <= 2) ++cntok;
    if (b == 3) ++cnt3;
    if (b >= 4) ++cnt4;
}
 
// rebuild dsu with exceptions
 
inline bool must_skip(int u) {
    if (mxdeg.first < 3)
        return false;
    if (u == mxdeg.second)
        return true;
    if (mxdeg.first == 3) {
        for (auto v : G[mxdeg.second]) if (v == u)
            return true;
    }
    return false;
}
 
inline void build_dsu() {
    //fprintf(stderr, "rebuild dsu!\n");
    ES.clear();
    mfcnt = 0;
    for (int i = 0; i < n; ++i)
        par[i] = i;
    for (auto e : E) {
        int u = e.first, v = e.second;
        if (must_skip(u) || must_skip(v)) {
            ES.emplace_back(u, v);
            //fprintf(stderr, "skip edge %d %d\n", u, v);
            continue;
        }
        merge(e.first, e.second);
    }
}
 
inline bool modify(int u) {
    ++deg[u];
    testmod(deg[u]-1, deg[u]);
    if (deg[u] > mxdeg.first) {
        mxdeg = pii(deg[u], u);
        if (mxdeg.first == 3 || mxdeg.first == 4) {
            ffc = false;
            return true;
        }
    }
    return false;
}
 
// testing functions
 
bool state4 = false;
bool dead[N];
inline bool test(int u) {
    //fprintf(stderr, "test(%d)\n", u);
    if (dead[u]) return false;
    if (!state4) {
        testmod(G[u].size(), 0);
        for (auto v : G[u])
            testmod(G[v].size(), G[v].size()-1);
        if (G[u].size() == 4) {
            deg[u] = 0;
            for (auto v : G[u]) --deg[v];
            state4 = true;
        }
    }
 
    bool ok = cnt3 == 0 && cnt4 == 0;
    ++tick;
    if (ok && !state4) for (auto e : ES) {
        if (e.first == u || e.second == u) continue;
        if (!nmerge(e.first, e.second)) ok = false;
        if (!ok) break;
    }
 
    if (!state4) {
        testmod(0, G[u].size());
        for (auto v : G[u])
            testmod(G[v].size()-1, G[v].size());
    }
 
    if (!ok) dead[u] = true;
    return ok;
}
 
// problem functions:
 
void Init(int n) {
    //fprintf(stderr, "Init(%d)\n", n);
    ::n = n;
    build_dsu();
}
 
void Link(int u, int v) {
    //fprintf(stderr, "Link(%d, %d)\n", u, v);
    G[u].push_back(v);
    G[v].push_back(u);
    if (state4 && (u == mxdeg.second || v == mxdeg.second))
        return;
    bool m = modify(u) | modify(v);
    E.emplace_back(u, v);
    if (m)
        build_dsu();
    else if (!must_skip(u) && !must_skip(v))
        merge(u, v);
    else
        ES.emplace_back(u, v);
}
 
int CountCritical() {
    //fprintf(stderr, "CountCritical()\n");
    if (state4) return mfcnt == 0 && test(mxdeg.second);
    if (mxdeg.first <= 2) {
        if (mfcnt > 1) return 0;
        else if (mfcnt == 1) return firstcycle;
        else if (mfcnt == 0) return n;
    }
    if (mfcnt > 0) return 0;
    int cnt = 0;
    if (test(mxdeg.second)) ++cnt;
    if (mxdeg.first == 3) {
        for (auto v : G[mxdeg.second])
            if (test(v)) ++cnt;
    }
    return cnt;
}

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 23876 KB Output is correct
2 Correct 24 ms 24072 KB Output is correct
3 Correct 24 ms 24252 KB Output is correct
4 Correct 22 ms 24252 KB Output is correct
5 Correct 23 ms 24252 KB Output is correct
6 Correct 25 ms 24548 KB Output is correct
7 Correct 22 ms 24548 KB Output is correct
8 Correct 23 ms 24548 KB Output is correct
9 Correct 24 ms 24548 KB Output is correct
10 Correct 24 ms 24548 KB Output is correct

Subtask #2
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 460 ms 48684 KB Output is correct
2 Correct 998 ms 61776 KB Output is correct
3 Correct 1236 ms 66516 KB Output is correct
4 Correct 1246 ms 71004 KB Output is correct
5 Correct 1264 ms 72408 KB Output is correct
6 Correct 1361 ms 100400 KB Output is correct
7 Correct 1133 ms 100400 KB Output is correct
8 Correct 1147 ms 100400 KB Output is correct
9 Correct 1252 ms 100400 KB Output is correct
10 Correct 885 ms 100400 KB Output is correct

Subtask #3
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 23876 KB Output is correct
2 Correct 24 ms 24072 KB Output is correct
3 Correct 24 ms 24252 KB Output is correct
4 Correct 22 ms 24252 KB Output is correct
5 Correct 23 ms 24252 KB Output is correct
6 Correct 25 ms 24548 KB Output is correct
7 Correct 22 ms 24548 KB Output is correct
8 Correct 23 ms 24548 KB Output is correct
9 Correct 24 ms 24548 KB Output is correct
10 Correct 24 ms 24548 KB Output is correct
11 Correct 25 ms 100400 KB Output is correct
12 Correct 27 ms 100400 KB Output is correct
13 Correct 27 ms 100400 KB Output is correct
14 Correct 26 ms 100400 KB Output is correct
15 Correct 35 ms 100400 KB Output is correct
16 Correct 28 ms 100400 KB Output is correct
17 Correct 27 ms 100400 KB Output is correct
18 Correct 28 ms 100400 KB Output is correct
19 Correct 29 ms 100400 KB Output is correct
20 Correct 29 ms 100400 KB Output is correct

Subtask #4
14.0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 23876 KB Output is correct
2 Correct 24 ms 24072 KB Output is correct
3 Correct 24 ms 24252 KB Output is correct
4 Correct 22 ms 24252 KB Output is correct
5 Correct 23 ms 24252 KB Output is correct
6 Correct 25 ms 24548 KB Output is correct
7 Correct 22 ms 24548 KB Output is correct
8 Correct 23 ms 24548 KB Output is correct
9 Correct 24 ms 24548 KB Output is correct
10 Correct 24 ms 24548 KB Output is correct
11 Correct 25 ms 100400 KB Output is correct
12 Correct 27 ms 100400 KB Output is correct
13 Correct 27 ms 100400 KB Output is correct
14 Correct 26 ms 100400 KB Output is correct
15 Correct 35 ms 100400 KB Output is correct
16 Correct 28 ms 100400 KB Output is correct
17 Correct 27 ms 100400 KB Output is correct
18 Correct 28 ms 100400 KB Output is correct
19 Correct 29 ms 100400 KB Output is correct
20 Correct 29 ms 100400 KB Output is correct
21 Correct 52 ms 100400 KB Output is correct
22 Correct 58 ms 100400 KB Output is correct
23 Correct 69 ms 100400 KB Output is correct
24 Correct 70 ms 100400 KB Output is correct
25 Correct 40 ms 100400 KB Output is correct
26 Correct 82 ms 100400 KB Output is correct
27 Correct 77 ms 100400 KB Output is correct
28 Correct 77 ms 100400 KB Output is correct
29 Correct 56 ms 100400 KB Output is correct
30 Correct 105 ms 100400 KB Output is correct

Subtask #5
31.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 23 ms 23876 KB Output is correct
2 Correct 24 ms 24072 KB Output is correct
3 Correct 24 ms 24252 KB Output is correct
4 Correct 22 ms 24252 KB Output is correct
5 Correct 23 ms 24252 KB Output is correct
6 Correct 25 ms 24548 KB Output is correct
7 Correct 22 ms 24548 KB Output is correct
8 Correct 23 ms 24548 KB Output is correct
9 Correct 24 ms 24548 KB Output is correct
10 Correct 24 ms 24548 KB Output is correct
11 Correct 460 ms 48684 KB Output is correct
12 Correct 998 ms 61776 KB Output is correct
13 Correct 1236 ms 66516 KB Output is correct
14 Correct 1246 ms 71004 KB Output is correct
15 Correct 1264 ms 72408 KB Output is correct
16 Correct 1361 ms 100400 KB Output is correct
17 Correct 1133 ms 100400 KB Output is correct
18 Correct 1147 ms 100400 KB Output is correct
19 Correct 1252 ms 100400 KB Output is correct
20 Correct 885 ms 100400 KB Output is correct
21 Correct 25 ms 100400 KB Output is correct
22 Correct 27 ms 100400 KB Output is correct
23 Correct 27 ms 100400 KB Output is correct
24 Correct 26 ms 100400 KB Output is correct
25 Correct 35 ms 100400 KB Output is correct
26 Correct 28 ms 100400 KB Output is correct
27 Correct 27 ms 100400 KB Output is correct
28 Correct 28 ms 100400 KB Output is correct
29 Correct 29 ms 100400 KB Output is correct
30 Correct 29 ms 100400 KB Output is correct
31 Correct 52 ms 100400 KB Output is correct
32 Correct 58 ms 100400 KB Output is correct
33 Correct 69 ms 100400 KB Output is correct
34 Correct 70 ms 100400 KB Output is correct
35 Correct 40 ms 100400 KB Output is correct
36 Correct 82 ms 100400 KB Output is correct
37 Correct 77 ms 100400 KB Output is correct
38 Correct 77 ms 100400 KB Output is correct
39 Correct 56 ms 100400 KB Output is correct
40 Correct 105 ms 100400 KB Output is correct
41 Correct 259 ms 100400 KB Output is correct
42 Correct 537 ms 100400 KB Output is correct
43 Correct 267 ms 100400 KB Output is correct
44 Correct 829 ms 100400 KB Output is correct
45 Correct 853 ms 100400 KB Output is correct
46 Correct 800 ms 100400 KB Output is correct
47 Correct 1119 ms 100400 KB Output is correct
48 Correct 555 ms 100400 KB Output is correct
49 Correct 814 ms 100400 KB Output is correct
50 Correct 875 ms 100400 KB Output is correct
51 Correct 299 ms 100400 KB Output is correct
52 Correct 732 ms 100400 KB Output is correct
53 Correct 598 ms 100400 KB Output is correct
54 Correct 1071 ms 100400 KB Output is correct
55 Correct 1114 ms 100400 KB Output is correct