oj.uz

Submission #66460

# Submission time Handle Problem Language Result Execution time Memory
66460 2018-08-10T15:59:24 Z aquablitz11 Parachute rings (IOI12_rings) C++14
55 / 100
 4000 ms 96412 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
 
inline bool test(int u) {
    //fprintf(stderr, "test(%d)\n", u);
    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());
 
    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;
    if (mxdeg.first == 3) {
        int cnt = 0;
        if (test(mxdeg.second)) ++cnt;
        for (auto v : G[mxdeg.second])
            if (test(v)) ++cnt;
        return cnt;
    }
    return test(mxdeg.second) ? 1 : 0;
}

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 22 ms 23800 KB Output is correct
2 Correct 24 ms 24180 KB Output is correct
3 Correct 25 ms 24296 KB Output is correct
4 Correct 22 ms 24296 KB Output is correct
5 Correct 25 ms 24296 KB Output is correct
6 Correct 24 ms 24504 KB Output is correct
7 Correct 23 ms 24504 KB Output is correct
8 Correct 23 ms 24504 KB Output is correct
9 Correct 26 ms 24508 KB Output is correct
10 Correct 25 ms 24508 KB Output is correct

Subtask #2
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 457 ms 46492 KB Output is correct
2 Correct 944 ms 58532 KB Output is correct
3 Correct 1179 ms 62760 KB Output is correct
4 Correct 1206 ms 67184 KB Output is correct
5 Correct 1223 ms 68516 KB Output is correct
6 Correct 1294 ms 96412 KB Output is correct
7 Correct 1171 ms 96412 KB Output is correct
8 Correct 1200 ms 96412 KB Output is correct
9 Correct 1338 ms 96412 KB Output is correct
10 Correct 898 ms 96412 KB Output is correct

Subtask #3
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 23800 KB Output is correct
2 Correct 24 ms 24180 KB Output is correct
3 Correct 25 ms 24296 KB Output is correct
4 Correct 22 ms 24296 KB Output is correct
5 Correct 25 ms 24296 KB Output is correct
6 Correct 24 ms 24504 KB Output is correct
7 Correct 23 ms 24504 KB Output is correct
8 Correct 23 ms 24504 KB Output is correct
9 Correct 26 ms 24508 KB Output is correct
10 Correct 25 ms 24508 KB Output is correct
11 Correct 28 ms 96412 KB Output is correct
12 Correct 35 ms 96412 KB Output is correct
13 Correct 30 ms 96412 KB Output is correct
14 Correct 30 ms 96412 KB Output is correct
15 Correct 30 ms 96412 KB Output is correct
16 Correct 39 ms 96412 KB Output is correct
17 Correct 31 ms 96412 KB Output is correct
18 Correct 30 ms 96412 KB Output is correct
19 Correct 33 ms 96412 KB Output is correct
20 Correct 29 ms 96412 KB Output is correct

Subtask #4
0 / 14.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 23800 KB Output is correct
2 Correct 24 ms 24180 KB Output is correct
3 Correct 25 ms 24296 KB Output is correct
4 Correct 22 ms 24296 KB Output is correct
5 Correct 25 ms 24296 KB Output is correct
6 Correct 24 ms 24504 KB Output is correct
7 Correct 23 ms 24504 KB Output is correct
8 Correct 23 ms 24504 KB Output is correct
9 Correct 26 ms 24508 KB Output is correct
10 Correct 25 ms 24508 KB Output is correct
11 Correct 28 ms 96412 KB Output is correct
12 Correct 35 ms 96412 KB Output is correct
13 Correct 30 ms 96412 KB Output is correct
14 Correct 30 ms 96412 KB Output is correct
15 Correct 30 ms 96412 KB Output is correct
16 Correct 39 ms 96412 KB Output is correct
17 Correct 31 ms 96412 KB Output is correct
18 Correct 30 ms 96412 KB Output is correct
19 Correct 33 ms 96412 KB Output is correct
20 Correct 29 ms 96412 KB Output is correct
21 Correct 65 ms 96412 KB Output is correct
22 Correct 73 ms 96412 KB Output is correct
23 Correct 80 ms 96412 KB Output is correct
24 Execution timed out 4033 ms 96412 KB Time limit exceeded
25 Halted 0 ms 0 KB -

Subtask #5
0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 22 ms 23800 KB Output is correct
2 Correct 24 ms 24180 KB Output is correct
3 Correct 25 ms 24296 KB Output is correct
4 Correct 22 ms 24296 KB Output is correct
5 Correct 25 ms 24296 KB Output is correct
6 Correct 24 ms 24504 KB Output is correct
7 Correct 23 ms 24504 KB Output is correct
8 Correct 23 ms 24504 KB Output is correct
9 Correct 26 ms 24508 KB Output is correct
10 Correct 25 ms 24508 KB Output is correct
11 Correct 457 ms 46492 KB Output is correct
12 Correct 944 ms 58532 KB Output is correct
13 Correct 1179 ms 62760 KB Output is correct
14 Correct 1206 ms 67184 KB Output is correct
15 Correct 1223 ms 68516 KB Output is correct
16 Correct 1294 ms 96412 KB Output is correct
17 Correct 1171 ms 96412 KB Output is correct
18 Correct 1200 ms 96412 KB Output is correct
19 Correct 1338 ms 96412 KB Output is correct
20 Correct 898 ms 96412 KB Output is correct
21 Correct 28 ms 96412 KB Output is correct
22 Correct 35 ms 96412 KB Output is correct
23 Correct 30 ms 96412 KB Output is correct
24 Correct 30 ms 96412 KB Output is correct
25 Correct 30 ms 96412 KB Output is correct
26 Correct 39 ms 96412 KB Output is correct
27 Correct 31 ms 96412 KB Output is correct
28 Correct 30 ms 96412 KB Output is correct
29 Correct 33 ms 96412 KB Output is correct
30 Correct 29 ms 96412 KB Output is correct
31 Correct 65 ms 96412 KB Output is correct
32 Correct 73 ms 96412 KB Output is correct
33 Correct 80 ms 96412 KB Output is correct
34 Execution timed out 4033 ms 96412 KB Time limit exceeded
35 Halted 0 ms 0 KB -