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Submission #956696

# Submission time Handle Problem Language Result Execution time Memory
956696 2024-04-02T10:57:43 Z GrindMachine Network (BOI15_net) C++17
100 / 100
 506 ms 89228 KB 
#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a,b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a,b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*



*/

const int MOD = 1e9 + 7;
const int N = 5e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

vector<ll> adj[N];
vector<ll> sub_leaves(N);

void dfs1(ll u, ll p){
    if(sz(adj[u]) == 1){
        sub_leaves[u] = 1;
    }

    trav(v,adj[u]){
        if(v == p) conts;
        dfs1(v,u);
        sub_leaves[u] += sub_leaves[v];
    }
}

ll dfs2(ll u, ll p, ll tot){
    trav(v,adj[u]){
        if(v == p) conts;
        if(sub_leaves[v] > tot/2){
            return dfs2(v,u,tot);
        }
    }

    return u;
}

vector<ll> leaves[N];

void dfs3(ll u, ll p, ll r){
    if(sz(adj[u]) == 1){
        leaves[r].pb(u);
    }

    trav(v,adj[u]){
        if(v == p) conts;
        dfs3(v,u,r);
    }
}

void solve(int test_case)
{
    ll n; cin >> n;
    rep1(i,n-1){
        ll u,v; cin >> u >> v;
        adj[u].pb(v), adj[v].pb(u);
    }

    ll root = -1;
    rep1(i,n){
        if(sz(adj[i]) >= 2){
            root = i;
            break;
        }
    }

    assert(root != -1);
    dfs1(root,-1);
    ll c = dfs2(root,-1,sub_leaves[root]);
    trav(v,adj[c]){
        dfs3(v,c,v);
    }

    vector<pll> ans;
    priority_queue<pll> pq;
    trav(v,adj[c]){
        pq.push({sz(leaves[v]),v});
    }

    while(sz(pq) >= 2){
        auto [s1,u] = pq.top();
        pq.pop();
        auto [s2,v] = pq.top();
        pq.pop();

        ll x = leaves[u].back();
        leaves[u].pop_back();
        ll y = leaves[v].back();
        leaves[v].pop_back();

        ans.pb({x,y});

        if(s1-1 >= 1){
            pq.push({s1-1,u});
        }
        if(s2-1 >= 1){
            pq.push({s2-1,v});
        }
    }

    if(!pq.empty()){
        auto [s1,u] = pq.top();
        pq.pop();

        assert(s1 == 1);
        ll x = leaves[u].back();
        leaves[u].pop_back();
        ans.pb({c,x});
    }

    assert(pq.empty());
    
    cout << sz(ans) << endl;
    for(auto [u,v] : ans){
        cout << u << " " << v << endl;
    }
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 27740 KB Output is correct
2 Correct 8 ms 27740 KB Output is correct
3 Correct 7 ms 27736 KB Output is correct
4 Correct 8 ms 27740 KB Output is correct
5 Correct 7 ms 27740 KB Output is correct
6 Correct 8 ms 27740 KB Output is correct
7 Correct 7 ms 27740 KB Output is correct
8 Correct 8 ms 27736 KB Output is correct
9 Correct 7 ms 27740 KB Output is correct
10 Correct 7 ms 27788 KB Output is correct
11 Correct 7 ms 27740 KB Output is correct
12 Correct 7 ms 27740 KB Output is correct
13 Correct 7 ms 27740 KB Output is correct
14 Correct 7 ms 27740 KB Output is correct
15 Correct 7 ms 27744 KB Output is correct
16 Correct 7 ms 27740 KB Output is correct
17 Correct 8 ms 27824 KB Output is correct
18 Correct 6 ms 27736 KB Output is correct
19 Correct 8 ms 28088 KB Output is correct
20 Correct 7 ms 27740 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 27740 KB Output is correct
2 Correct 8 ms 27740 KB Output is correct
3 Correct 7 ms 27736 KB Output is correct
4 Correct 8 ms 27740 KB Output is correct
5 Correct 7 ms 27740 KB Output is correct
6 Correct 8 ms 27740 KB Output is correct
7 Correct 7 ms 27740 KB Output is correct
8 Correct 8 ms 27736 KB Output is correct
9 Correct 7 ms 27740 KB Output is correct
10 Correct 7 ms 27788 KB Output is correct
11 Correct 7 ms 27740 KB Output is correct
12 Correct 7 ms 27740 KB Output is correct
13 Correct 7 ms 27740 KB Output is correct
14 Correct 7 ms 27740 KB Output is correct
15 Correct 7 ms 27744 KB Output is correct
16 Correct 7 ms 27740 KB Output is correct
17 Correct 8 ms 27824 KB Output is correct
18 Correct 6 ms 27736 KB Output is correct
19 Correct 8 ms 28088 KB Output is correct
20 Correct 7 ms 27740 KB Output is correct
21 Correct 7 ms 27740 KB Output is correct
22 Correct 8 ms 27824 KB Output is correct
23 Correct 8 ms 27996 KB Output is correct
24 Correct 8 ms 27996 KB Output is correct
25 Correct 7 ms 27996 KB Output is correct
26 Correct 7 ms 27740 KB Output is correct
27 Correct 7 ms 27996 KB Output is correct
28 Correct 7 ms 27996 KB Output is correct
29 Correct 7 ms 27740 KB Output is correct
30 Correct 6 ms 27740 KB Output is correct
31 Correct 7 ms 27992 KB Output is correct
32 Correct 7 ms 27740 KB Output is correct
33 Correct 6 ms 27740 KB Output is correct
34 Correct 8 ms 27740 KB Output is correct
35 Correct 7 ms 27832 KB Output is correct
36 Correct 6 ms 27736 KB Output is correct
37 Correct 7 ms 27740 KB Output is correct
38 Correct 7 ms 27736 KB Output is correct
39 Correct 6 ms 27740 KB Output is correct
40 Correct 6 ms 27740 KB Output is correct
41 Correct 7 ms 27740 KB Output is correct
42 Correct 7 ms 27740 KB Output is correct
43 Correct 7 ms 27740 KB Output is correct
44 Correct 6 ms 27740 KB Output is correct
45 Correct 7 ms 27740 KB Output is correct
46 Correct 7 ms 27740 KB Output is correct
47 Correct 7 ms 27688 KB Output is correct
48 Correct 7 ms 27752 KB Output is correct
49 Correct 7 ms 27740 KB Output is correct
50 Correct 7 ms 27740 KB Output is correct
51 Correct 6 ms 27736 KB Output is correct
52 Correct 8 ms 27740 KB Output is correct
53 Correct 7 ms 27740 KB Output is correct
54 Correct 7 ms 27740 KB Output is correct
55 Correct 7 ms 27740 KB Output is correct
56 Correct 7 ms 27828 KB Output is correct
57 Correct 7 ms 27736 KB Output is correct
58 Correct 7 ms 27996 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 27740 KB Output is correct
2 Correct 8 ms 27740 KB Output is correct
3 Correct 7 ms 27736 KB Output is correct
4 Correct 8 ms 27740 KB Output is correct
5 Correct 7 ms 27740 KB Output is correct
6 Correct 8 ms 27740 KB Output is correct
7 Correct 7 ms 27740 KB Output is correct
8 Correct 8 ms 27736 KB Output is correct
9 Correct 7 ms 27740 KB Output is correct
10 Correct 7 ms 27788 KB Output is correct
11 Correct 7 ms 27740 KB Output is correct
12 Correct 7 ms 27740 KB Output is correct
13 Correct 7 ms 27740 KB Output is correct
14 Correct 7 ms 27740 KB Output is correct
15 Correct 7 ms 27744 KB Output is correct
16 Correct 7 ms 27740 KB Output is correct
17 Correct 8 ms 27824 KB Output is correct
18 Correct 6 ms 27736 KB Output is correct
19 Correct 8 ms 28088 KB Output is correct
20 Correct 7 ms 27740 KB Output is correct
21 Correct 7 ms 27740 KB Output is correct
22 Correct 8 ms 27824 KB Output is correct
23 Correct 8 ms 27996 KB Output is correct
24 Correct 8 ms 27996 KB Output is correct
25 Correct 7 ms 27996 KB Output is correct
26 Correct 7 ms 27740 KB Output is correct
27 Correct 7 ms 27996 KB Output is correct
28 Correct 7 ms 27996 KB Output is correct
29 Correct 7 ms 27740 KB Output is correct
30 Correct 6 ms 27740 KB Output is correct
31 Correct 7 ms 27992 KB Output is correct
32 Correct 7 ms 27740 KB Output is correct
33 Correct 6 ms 27740 KB Output is correct
34 Correct 8 ms 27740 KB Output is correct
35 Correct 7 ms 27832 KB Output is correct
36 Correct 6 ms 27736 KB Output is correct
37 Correct 7 ms 27740 KB Output is correct
38 Correct 7 ms 27736 KB Output is correct
39 Correct 6 ms 27740 KB Output is correct
40 Correct 6 ms 27740 KB Output is correct
41 Correct 7 ms 27740 KB Output is correct
42 Correct 7 ms 27740 KB Output is correct
43 Correct 7 ms 27740 KB Output is correct
44 Correct 6 ms 27740 KB Output is correct
45 Correct 7 ms 27740 KB Output is correct
46 Correct 7 ms 27740 KB Output is correct
47 Correct 7 ms 27688 KB Output is correct
48 Correct 7 ms 27752 KB Output is correct
49 Correct 7 ms 27740 KB Output is correct
50 Correct 7 ms 27740 KB Output is correct
51 Correct 6 ms 27736 KB Output is correct
52 Correct 8 ms 27740 KB Output is correct
53 Correct 7 ms 27740 KB Output is correct
54 Correct 7 ms 27740 KB Output is correct
55 Correct 7 ms 27740 KB Output is correct
56 Correct 7 ms 27828 KB Output is correct
57 Correct 7 ms 27736 KB Output is correct
58 Correct 7 ms 27996 KB Output is correct
59 Correct 381 ms 66468 KB Output is correct
60 Correct 345 ms 63120 KB Output is correct
61 Correct 7 ms 27736 KB Output is correct
62 Correct 7 ms 27992 KB Output is correct
63 Correct 314 ms 60448 KB Output is correct
64 Correct 8 ms 28252 KB Output is correct
65 Correct 15 ms 29528 KB Output is correct
66 Correct 116 ms 43744 KB Output is correct
67 Correct 487 ms 66896 KB Output is correct
68 Correct 450 ms 66256 KB Output is correct
69 Correct 14 ms 29404 KB Output is correct
70 Correct 96 ms 47680 KB Output is correct
71 Correct 422 ms 89228 KB Output is correct
72 Correct 436 ms 85248 KB Output is correct
73 Correct 62 ms 36488 KB Output is correct
74 Correct 348 ms 58948 KB Output is correct
75 Correct 30 ms 32844 KB Output is correct
76 Correct 329 ms 74216 KB Output is correct
77 Correct 337 ms 75308 KB Output is correct
78 Correct 26 ms 31572 KB Output is correct
79 Correct 506 ms 60868 KB Output is correct
80 Correct 9 ms 27996 KB Output is correct
81 Correct 93 ms 43528 KB Output is correct
82 Correct 394 ms 73172 KB Output is correct
83 Correct 369 ms 58868 KB Output is correct
84 Correct 374 ms 59976 KB Output is correct
85 Correct 382 ms 59900 KB Output is correct
86 Correct 359 ms 64728 KB Output is correct
87 Correct 356 ms 63952 KB Output is correct