oj.uz

Submission #926738

# Submission time Handle Problem Language Result Execution time Memory
926738 2024-02-13T15:08:59 Z Regulus Network (BOI15_net) C++17
63 / 100
 2000 ms 58568 KB 
#include <bits/stdc++.h>
#define IO ios::sync_with_stdio(false);cin.tie(0);
#define debug(x) cerr << #x << " = " << (x) << ' '
#define bug(x) cerr << (x) << ' '
#define endl cerr << '\n'
#define all(v) (v).begin(), (v).end()
#define SZ(v) (ll)(v).size()
#define lowbit(x) (x)&-(x)
#define pb emplace_back
#define F first
#define S second
using namespace std;
using ll = long long;
using pll = pair<ll, ll>;

const int N = 5e5+5;
int n, dis[N], fa[N], dsu[N];
pll e[N];
vector<int> g[N];
vector<pll> v2;

inline int query(int x) { return (dsu[x]<0)?x : dsu[x]=query(dsu[x]); }
inline bool unite(int x, int y)
{
    x = query(x), y = query(y); if (x == y) return 0;
    dsu[y] = x; return 1;
}

inline void dfs(int x, int pre)
{
    dis[x] = dis[pre] + 1, fa[x] = pre;
    for (int v : g[x]) if (v != pre) dfs(v, x);
}

inline pll find_dis()
{
    int pos = query(1), pos2;
    dfs(pos, 0);
    for (int i=1; i <= n; ++i)
        if (dsu[i] == -1 && dis[i] > dis[pos]) pos = i;
    dfs(pos, 0), pos2 = pos;
    for (int i=1; i <= n; ++i)
        if (dsu[i] == -1 && dis[i] > dis[pos2]) pos2 = i;
    return {pos, pos2};
}

int main(void)
{ IO
    int i, x, y;
    
    cin >> n;
    for (i=1; i <= n-1; ++i) cin >> x >> y, e[i] = {x, y};

    int cnt = n;
    for (i=1; i <= n; ++i) dsu[i] = -1;
    while (cnt > 1)
    {
        //debug(cnt), endl;
        for (i=1; i <= n; ++i) g[i].clear();
        for (i=1; i <= n-1; ++i)
        {
            x = query(e[i].F), y = query(e[i].S);
            //if (x != y) debug(x), debug(y), endl;
            if (x != y) g[x].pb(y), g[y].pb(x);
        }

        auto tp = find_dis();
        v2.pb(tp.F, tp.S);
        int cur = tp.S;
        do {
            if (fa[cur]) cnt -= unite(cur, fa[cur]);
            cur = fa[cur];
        } while (cur);
        //debug(dis[tp.S]-1), debug(cnt), endl;
        //for (i=1; i <= n; ++i) bug(query(i)); endl;
    }
    
    cout << SZ(v2) << '\n';
    for (auto p : v2) cout << p.F << ' ' << p.S << '\n';

    return 0;
}

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 17000 KB Output is correct
2 Correct 4 ms 16988 KB Output is correct
3 Correct 4 ms 16984 KB Output is correct
4 Correct 4 ms 16988 KB Output is correct
5 Correct 3 ms 17040 KB Output is correct
6 Correct 3 ms 16984 KB Output is correct
7 Correct 3 ms 16988 KB Output is correct
8 Correct 3 ms 16988 KB Output is correct
9 Correct 3 ms 16988 KB Output is correct
10 Correct 3 ms 16988 KB Output is correct
11 Correct 4 ms 17040 KB Output is correct
12 Correct 3 ms 16984 KB Output is correct
13 Correct 3 ms 17056 KB Output is correct
14 Correct 3 ms 16988 KB Output is correct
15 Correct 3 ms 16988 KB Output is correct
16 Correct 3 ms 16988 KB Output is correct
17 Correct 4 ms 16988 KB Output is correct
18 Correct 3 ms 16988 KB Output is correct
19 Correct 3 ms 16988 KB Output is correct
20 Correct 3 ms 16988 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 17000 KB Output is correct
2 Correct 4 ms 16988 KB Output is correct
3 Correct 4 ms 16984 KB Output is correct
4 Correct 4 ms 16988 KB Output is correct
5 Correct 3 ms 17040 KB Output is correct
6 Correct 3 ms 16984 KB Output is correct
7 Correct 3 ms 16988 KB Output is correct
8 Correct 3 ms 16988 KB Output is correct
9 Correct 3 ms 16988 KB Output is correct
10 Correct 3 ms 16988 KB Output is correct
11 Correct 4 ms 17040 KB Output is correct
12 Correct 3 ms 16984 KB Output is correct
13 Correct 3 ms 17056 KB Output is correct
14 Correct 3 ms 16988 KB Output is correct
15 Correct 3 ms 16988 KB Output is correct
16 Correct 3 ms 16988 KB Output is correct
17 Correct 4 ms 16988 KB Output is correct
18 Correct 3 ms 16988 KB Output is correct
19 Correct 3 ms 16988 KB Output is correct
20 Correct 3 ms 16988 KB Output is correct
21 Correct 3 ms 16988 KB Output is correct
22 Correct 33 ms 22296 KB Output is correct
23 Correct 29 ms 21976 KB Output is correct
24 Correct 30 ms 21964 KB Output is correct
25 Correct 21 ms 18780 KB Output is correct
26 Correct 15 ms 18520 KB Output is correct
27 Correct 24 ms 19036 KB Output is correct
28 Correct 22 ms 18840 KB Output is correct
29 Correct 15 ms 18268 KB Output is correct
30 Correct 4 ms 17240 KB Output is correct
31 Correct 24 ms 19292 KB Output is correct
32 Correct 3 ms 16984 KB Output is correct
33 Correct 3 ms 16988 KB Output is correct
34 Correct 3 ms 16988 KB Output is correct
35 Correct 3 ms 16988 KB Output is correct
36 Correct 3 ms 16988 KB Output is correct
37 Correct 4 ms 16988 KB Output is correct
38 Correct 4 ms 16988 KB Output is correct
39 Correct 3 ms 16988 KB Output is correct
40 Correct 3 ms 16988 KB Output is correct
41 Correct 4 ms 17040 KB Output is correct
42 Correct 6 ms 17244 KB Output is correct
43 Correct 10 ms 18264 KB Output is correct
44 Correct 3 ms 16984 KB Output is correct
45 Correct 5 ms 16988 KB Output is correct
46 Correct 7 ms 17432 KB Output is correct
47 Correct 3 ms 16988 KB Output is correct
48 Correct 4 ms 16988 KB Output is correct
49 Correct 10 ms 18264 KB Output is correct
50 Correct 3 ms 16988 KB Output is correct
51 Correct 3 ms 16988 KB Output is correct
52 Correct 3 ms 16988 KB Output is correct
53 Correct 5 ms 17244 KB Output is correct
54 Correct 3 ms 16988 KB Output is correct
55 Correct 4 ms 16988 KB Output is correct
56 Correct 3 ms 16988 KB Output is correct
57 Correct 6 ms 17244 KB Output is correct
58 Correct 30 ms 22432 KB Output is correct

Subtask #3
0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 17000 KB Output is correct
2 Correct 4 ms 16988 KB Output is correct
3 Correct 4 ms 16984 KB Output is correct
4 Correct 4 ms 16988 KB Output is correct
5 Correct 3 ms 17040 KB Output is correct
6 Correct 3 ms 16984 KB Output is correct
7 Correct 3 ms 16988 KB Output is correct
8 Correct 3 ms 16988 KB Output is correct
9 Correct 3 ms 16988 KB Output is correct
10 Correct 3 ms 16988 KB Output is correct
11 Correct 4 ms 17040 KB Output is correct
12 Correct 3 ms 16984 KB Output is correct
13 Correct 3 ms 17056 KB Output is correct
14 Correct 3 ms 16988 KB Output is correct
15 Correct 3 ms 16988 KB Output is correct
16 Correct 3 ms 16988 KB Output is correct
17 Correct 4 ms 16988 KB Output is correct
18 Correct 3 ms 16988 KB Output is correct
19 Correct 3 ms 16988 KB Output is correct
20 Correct 3 ms 16988 KB Output is correct
21 Correct 3 ms 16988 KB Output is correct
22 Correct 33 ms 22296 KB Output is correct
23 Correct 29 ms 21976 KB Output is correct
24 Correct 30 ms 21964 KB Output is correct
25 Correct 21 ms 18780 KB Output is correct
26 Correct 15 ms 18520 KB Output is correct
27 Correct 24 ms 19036 KB Output is correct
28 Correct 22 ms 18840 KB Output is correct
29 Correct 15 ms 18268 KB Output is correct
30 Correct 4 ms 17240 KB Output is correct
31 Correct 24 ms 19292 KB Output is correct
32 Correct 3 ms 16984 KB Output is correct
33 Correct 3 ms 16988 KB Output is correct
34 Correct 3 ms 16988 KB Output is correct
35 Correct 3 ms 16988 KB Output is correct
36 Correct 3 ms 16988 KB Output is correct
37 Correct 4 ms 16988 KB Output is correct
38 Correct 4 ms 16988 KB Output is correct
39 Correct 3 ms 16988 KB Output is correct
40 Correct 3 ms 16988 KB Output is correct
41 Correct 4 ms 17040 KB Output is correct
42 Correct 6 ms 17244 KB Output is correct
43 Correct 10 ms 18264 KB Output is correct
44 Correct 3 ms 16984 KB Output is correct
45 Correct 5 ms 16988 KB Output is correct
46 Correct 7 ms 17432 KB Output is correct
47 Correct 3 ms 16988 KB Output is correct
48 Correct 4 ms 16988 KB Output is correct
49 Correct 10 ms 18264 KB Output is correct
50 Correct 3 ms 16988 KB Output is correct
51 Correct 3 ms 16988 KB Output is correct
52 Correct 3 ms 16988 KB Output is correct
53 Correct 5 ms 17244 KB Output is correct
54 Correct 3 ms 16988 KB Output is correct
55 Correct 4 ms 16988 KB Output is correct
56 Correct 3 ms 16988 KB Output is correct
57 Correct 6 ms 17244 KB Output is correct
58 Correct 30 ms 22432 KB Output is correct
59 Execution timed out 2063 ms 58568 KB Time limit exceeded
60 Halted 0 ms 0 KB -