oj.uz

Submission #66461

# Submission time Handle Problem Language Result Execution time Memory
66461 2018-08-10T16:01:26 Z aquablitz11 Parachute rings (IOI12_rings) C++14
55 / 100
 4000 ms 96524 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;
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) {
    testmod(G[u].size()-1, G[u].size());
    if (G[u].size() > mxdeg.first) {
        mxdeg = pii(G[u].size(), u);
        if (mxdeg.first == 3 || mxdeg.first == 4) {
            ffc = false;
            return true;
        }
    }
    return false;
}
 
// testing functions
 
bool dead[N];
inline bool test(int u) {
    //fprintf(stderr, "test(%d)\n", u);
    if (dead[u]) return false;
    testmod(G[u].size(), 0);
    for (auto v : G[u])
        testmod(G[v].size(), G[v].size()-1);
 
    bool ok = cnt3 == 0 && cnt4 == 0;
    ++tick;
    if (ok) for (auto e : ES) {
        if (e.first == u || e.second == u) continue;
        if (!nmerge(e.first, e.second)) ok = false;
        if (!ok) break;
    }
 
    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);
    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 (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;
}

Compilation message

rings.cpp: In function 'bool modify(int)':
rings.cpp:110:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     if (G[u].size() > mxdeg.first) {
         ~~~~~~~~~~~~^~~~~~~~~~~~~

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 23800 KB Output is correct
2 Correct 23 ms 24052 KB Output is correct
3 Correct 25 ms 24344 KB Output is correct
4 Correct 23 ms 24344 KB Output is correct
5 Correct 23 ms 24344 KB Output is correct
6 Correct 24 ms 24524 KB Output is correct
7 Correct 23 ms 24524 KB Output is correct
8 Correct 24 ms 24524 KB Output is correct
9 Correct 24 ms 24524 KB Output is correct
10 Correct 26 ms 24524 KB Output is correct

Subtask #2
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 480 ms 46508 KB Output is correct
2 Correct 923 ms 58560 KB Output is correct
3 Correct 1242 ms 62776 KB Output is correct
4 Correct 1204 ms 67124 KB Output is correct
5 Correct 1189 ms 68372 KB Output is correct
6 Correct 1310 ms 96524 KB Output is correct
7 Correct 1105 ms 96524 KB Output is correct
8 Correct 1163 ms 96524 KB Output is correct
9 Correct 1209 ms 96524 KB Output is correct
10 Correct 901 ms 96524 KB Output is correct

Subtask #3
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 23800 KB Output is correct
2 Correct 23 ms 24052 KB Output is correct
3 Correct 25 ms 24344 KB Output is correct
4 Correct 23 ms 24344 KB Output is correct
5 Correct 23 ms 24344 KB Output is correct
6 Correct 24 ms 24524 KB Output is correct
7 Correct 23 ms 24524 KB Output is correct
8 Correct 24 ms 24524 KB Output is correct
9 Correct 24 ms 24524 KB Output is correct
10 Correct 26 ms 24524 KB Output is correct
11 Correct 27 ms 96524 KB Output is correct
12 Correct 32 ms 96524 KB Output is correct
13 Correct 28 ms 96524 KB Output is correct
14 Correct 27 ms 96524 KB Output is correct
15 Correct 30 ms 96524 KB Output is correct
16 Correct 27 ms 96524 KB Output is correct
17 Correct 27 ms 96524 KB Output is correct
18 Correct 30 ms 96524 KB Output is correct
19 Correct 27 ms 96524 KB Output is correct
20 Correct 27 ms 96524 KB Output is correct

Subtask #4
0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 23800 KB Output is correct
2 Correct 23 ms 24052 KB Output is correct
3 Correct 25 ms 24344 KB Output is correct
4 Correct 23 ms 24344 KB Output is correct
5 Correct 23 ms 24344 KB Output is correct
6 Correct 24 ms 24524 KB Output is correct
7 Correct 23 ms 24524 KB Output is correct
8 Correct 24 ms 24524 KB Output is correct
9 Correct 24 ms 24524 KB Output is correct
10 Correct 26 ms 24524 KB Output is correct
11 Correct 27 ms 96524 KB Output is correct
12 Correct 32 ms 96524 KB Output is correct
13 Correct 28 ms 96524 KB Output is correct
14 Correct 27 ms 96524 KB Output is correct
15 Correct 30 ms 96524 KB Output is correct
16 Correct 27 ms 96524 KB Output is correct
17 Correct 27 ms 96524 KB Output is correct
18 Correct 30 ms 96524 KB Output is correct
19 Correct 27 ms 96524 KB Output is correct
20 Correct 27 ms 96524 KB Output is correct
21 Correct 41 ms 96524 KB Output is correct
22 Correct 57 ms 96524 KB Output is correct
23 Correct 73 ms 96524 KB Output is correct
24 Execution timed out 4038 ms 96524 KB Time limit exceeded
25 Halted 0 ms 0 KB -

Subtask #5
0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 24 ms 23800 KB Output is correct
2 Correct 23 ms 24052 KB Output is correct
3 Correct 25 ms 24344 KB Output is correct
4 Correct 23 ms 24344 KB Output is correct
5 Correct 23 ms 24344 KB Output is correct
6 Correct 24 ms 24524 KB Output is correct
7 Correct 23 ms 24524 KB Output is correct
8 Correct 24 ms 24524 KB Output is correct
9 Correct 24 ms 24524 KB Output is correct
10 Correct 26 ms 24524 KB Output is correct
11 Correct 480 ms 46508 KB Output is correct
12 Correct 923 ms 58560 KB Output is correct
13 Correct 1242 ms 62776 KB Output is correct
14 Correct 1204 ms 67124 KB Output is correct
15 Correct 1189 ms 68372 KB Output is correct
16 Correct 1310 ms 96524 KB Output is correct
17 Correct 1105 ms 96524 KB Output is correct
18 Correct 1163 ms 96524 KB Output is correct
19 Correct 1209 ms 96524 KB Output is correct
20 Correct 901 ms 96524 KB Output is correct
21 Correct 27 ms 96524 KB Output is correct
22 Correct 32 ms 96524 KB Output is correct
23 Correct 28 ms 96524 KB Output is correct
24 Correct 27 ms 96524 KB Output is correct
25 Correct 30 ms 96524 KB Output is correct
26 Correct 27 ms 96524 KB Output is correct
27 Correct 27 ms 96524 KB Output is correct
28 Correct 30 ms 96524 KB Output is correct
29 Correct 27 ms 96524 KB Output is correct
30 Correct 27 ms 96524 KB Output is correct
31 Correct 41 ms 96524 KB Output is correct
32 Correct 57 ms 96524 KB Output is correct
33 Correct 73 ms 96524 KB Output is correct
34 Execution timed out 4038 ms 96524 KB Time limit exceeded
35 Halted 0 ms 0 KB -