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Submission #828761

# Submission time Handle Problem Language Result Execution time Memory
828761 2023-08-17T15:24:26 Z bachhoangxuan Network (BOI15_net) C++17
100 / 100
 563 ms 252288 KB 
// Judges with GCC >= 12 only needs Ofast
// #pragma GCC optimize("O3,no-stack-protector,fast-math,unroll-loops,tree-vectorize")
// MLE optimization
// #pragma GCC optimize("conserve-stack")
// Old judges
// #pragma GCC target("sse4.2,popcnt,lzcnt,abm,mmx,fma,bmi,bmi2")
// New judges. Test with assert(__builtin_cpu_supports("avx2"));
// #pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma,tune=native")
// Atcoder
// #pragma GCC target("avx2,popcnt,lzcnt,abm,bmi,bmi2,fma")
/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
typedef tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> ordered_set;
- insert(x),erase(x)
- find_by_order(k): return iterator to the k-th smallest element
- order_of_key(x): the number of elements that are strictly smaller
*/
#include<bits/stdc++.h>
using namespace std;
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
uniform_real_distribution<> pp(0.0,1.0);
//#define int long long
#define ld long double
#define pii pair<int,int>
#define piii pair<int,pii>
#define mpp make_pair
#define fi first
#define se second
//const int inf=1e18;
const int mod=998244353;
const int maxn=500005;
const int bl=650;
const int maxs=655;
const int maxm=200005;
const int maxq=1000005;
const int maxl=20;
const int maxa=1000000;
const int root=3;
/*
int power(int a,int n){
    int res=1;
    while(n){
        if(n&1) res=res*a%mod;
        a=a*a%mod;n>>=1;
    }
    return res;
}
const int iroot=power(3,mod-2);
*/
const int base=101;

pii p[maxn];
vector<pii> ans;
vector<int> edge[maxn];
void dfs(int u,int par){
    if((int)edge[u].size()==1){
        p[u]={-1,u};
        return;
    }
    deque<int> f1;
    pii f2={-1,-1};
    for(int v:edge[u]){
        if(v==par) continue;
        dfs(v,u);
        if(p[v].fi==-1) f1.push_back(p[v].se);
        else if(f2.fi==-1) f2=p[v];
        else{
            ans.push_back({f2.se,p[v].fi});
            f2.se=p[v].se;
        }
    }
    if(f2.fi!=-1){
        f1.push_front(f2.fi);
        f1.push_back(f2.se);
    }
    while((int)f1.size()>=3){
        int x=f1.back();f1.pop_back();
        int y=f1.back();f1.pop_back();
        ans.push_back({x,y});
    }
    if((int)f1.size()>=2) p[u]={f1[0],f1[1]};
    else p[u]={-1,f1[0]};
}
void solve(){
    int n;cin >> n;
    for(int i=1;i<n;i++){
        int u,v;cin >> u >> v;
        edge[u].push_back(v);
        edge[v].push_back(u);
    }
    int rt=1;
    while((int)edge[rt].size()==1) rt++;
    dfs(rt,0);
    if(p[rt].fi==-1) ans.push_back({rt,p[rt].se});
    else ans.push_back(p[rt]);
    cout << (int)ans.size() << '\n';
    for(auto &[x,y]:ans) cout << x << ' ' << y << '\n';
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);cout.tie(NULL);
    int test=1;//cin >> test;
    while(test--) solve();
}

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 11988 KB Output is correct
2 Correct 6 ms 11988 KB Output is correct
3 Correct 6 ms 12000 KB Output is correct
4 Correct 5 ms 12076 KB Output is correct
5 Correct 5 ms 11988 KB Output is correct
6 Correct 5 ms 12076 KB Output is correct
7 Correct 5 ms 11988 KB Output is correct
8 Correct 6 ms 12076 KB Output is correct
9 Correct 7 ms 12072 KB Output is correct
10 Correct 6 ms 12076 KB Output is correct
11 Correct 7 ms 12068 KB Output is correct
12 Correct 6 ms 12052 KB Output is correct
13 Correct 7 ms 12072 KB Output is correct
14 Correct 7 ms 12008 KB Output is correct
15 Correct 6 ms 11988 KB Output is correct
16 Correct 6 ms 11988 KB Output is correct
17 Correct 6 ms 11988 KB Output is correct
18 Correct 6 ms 11988 KB Output is correct
19 Correct 6 ms 12072 KB Output is correct
20 Correct 5 ms 11988 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 11988 KB Output is correct
2 Correct 6 ms 11988 KB Output is correct
3 Correct 6 ms 12000 KB Output is correct
4 Correct 5 ms 12076 KB Output is correct
5 Correct 5 ms 11988 KB Output is correct
6 Correct 5 ms 12076 KB Output is correct
7 Correct 5 ms 11988 KB Output is correct
8 Correct 6 ms 12076 KB Output is correct
9 Correct 7 ms 12072 KB Output is correct
10 Correct 6 ms 12076 KB Output is correct
11 Correct 7 ms 12068 KB Output is correct
12 Correct 6 ms 12052 KB Output is correct
13 Correct 7 ms 12072 KB Output is correct
14 Correct 7 ms 12008 KB Output is correct
15 Correct 6 ms 11988 KB Output is correct
16 Correct 6 ms 11988 KB Output is correct
17 Correct 6 ms 11988 KB Output is correct
18 Correct 6 ms 11988 KB Output is correct
19 Correct 6 ms 12072 KB Output is correct
20 Correct 5 ms 11988 KB Output is correct
21 Correct 6 ms 12072 KB Output is correct
22 Correct 6 ms 12116 KB Output is correct
23 Correct 6 ms 12100 KB Output is correct
24 Correct 9 ms 12244 KB Output is correct
25 Correct 6 ms 12176 KB Output is correct
26 Correct 6 ms 12116 KB Output is correct
27 Correct 8 ms 12084 KB Output is correct
28 Correct 6 ms 12092 KB Output is correct
29 Correct 6 ms 12092 KB Output is correct
30 Correct 6 ms 11988 KB Output is correct
31 Correct 8 ms 12088 KB Output is correct
32 Correct 6 ms 12080 KB Output is correct
33 Correct 6 ms 11988 KB Output is correct
34 Correct 6 ms 11988 KB Output is correct
35 Correct 6 ms 12080 KB Output is correct
36 Correct 6 ms 12084 KB Output is correct
37 Correct 7 ms 12300 KB Output is correct
38 Correct 7 ms 12628 KB Output is correct
39 Correct 6 ms 12072 KB Output is correct
40 Correct 6 ms 12076 KB Output is correct
41 Correct 6 ms 11988 KB Output is correct
42 Correct 6 ms 12104 KB Output is correct
43 Correct 6 ms 12116 KB Output is correct
44 Correct 6 ms 11988 KB Output is correct
45 Correct 6 ms 11988 KB Output is correct
46 Correct 6 ms 12116 KB Output is correct
47 Correct 6 ms 12076 KB Output is correct
48 Correct 6 ms 11988 KB Output is correct
49 Correct 6 ms 12084 KB Output is correct
50 Correct 5 ms 11988 KB Output is correct
51 Correct 6 ms 12072 KB Output is correct
52 Correct 6 ms 12116 KB Output is correct
53 Correct 6 ms 12208 KB Output is correct
54 Correct 6 ms 12072 KB Output is correct
55 Correct 6 ms 11988 KB Output is correct
56 Correct 5 ms 11988 KB Output is correct
57 Correct 6 ms 12068 KB Output is correct
58 Correct 8 ms 12112 KB Output is correct

Subtask #3
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 11988 KB Output is correct
2 Correct 6 ms 11988 KB Output is correct
3 Correct 6 ms 12000 KB Output is correct
4 Correct 5 ms 12076 KB Output is correct
5 Correct 5 ms 11988 KB Output is correct
6 Correct 5 ms 12076 KB Output is correct
7 Correct 5 ms 11988 KB Output is correct
8 Correct 6 ms 12076 KB Output is correct
9 Correct 7 ms 12072 KB Output is correct
10 Correct 6 ms 12076 KB Output is correct
11 Correct 7 ms 12068 KB Output is correct
12 Correct 6 ms 12052 KB Output is correct
13 Correct 7 ms 12072 KB Output is correct
14 Correct 7 ms 12008 KB Output is correct
15 Correct 6 ms 11988 KB Output is correct
16 Correct 6 ms 11988 KB Output is correct
17 Correct 6 ms 11988 KB Output is correct
18 Correct 6 ms 11988 KB Output is correct
19 Correct 6 ms 12072 KB Output is correct
20 Correct 5 ms 11988 KB Output is correct
21 Correct 6 ms 12072 KB Output is correct
22 Correct 6 ms 12116 KB Output is correct
23 Correct 6 ms 12100 KB Output is correct
24 Correct 9 ms 12244 KB Output is correct
25 Correct 6 ms 12176 KB Output is correct
26 Correct 6 ms 12116 KB Output is correct
27 Correct 8 ms 12084 KB Output is correct
28 Correct 6 ms 12092 KB Output is correct
29 Correct 6 ms 12092 KB Output is correct
30 Correct 6 ms 11988 KB Output is correct
31 Correct 8 ms 12088 KB Output is correct
32 Correct 6 ms 12080 KB Output is correct
33 Correct 6 ms 11988 KB Output is correct
34 Correct 6 ms 11988 KB Output is correct
35 Correct 6 ms 12080 KB Output is correct
36 Correct 6 ms 12084 KB Output is correct
37 Correct 7 ms 12300 KB Output is correct
38 Correct 7 ms 12628 KB Output is correct
39 Correct 6 ms 12072 KB Output is correct
40 Correct 6 ms 12076 KB Output is correct
41 Correct 6 ms 11988 KB Output is correct
42 Correct 6 ms 12104 KB Output is correct
43 Correct 6 ms 12116 KB Output is correct
44 Correct 6 ms 11988 KB Output is correct
45 Correct 6 ms 11988 KB Output is correct
46 Correct 6 ms 12116 KB Output is correct
47 Correct 6 ms 12076 KB Output is correct
48 Correct 6 ms 11988 KB Output is correct
49 Correct 6 ms 12084 KB Output is correct
50 Correct 5 ms 11988 KB Output is correct
51 Correct 6 ms 12072 KB Output is correct
52 Correct 6 ms 12116 KB Output is correct
53 Correct 6 ms 12208 KB Output is correct
54 Correct 6 ms 12072 KB Output is correct
55 Correct 6 ms 11988 KB Output is correct
56 Correct 5 ms 11988 KB Output is correct
57 Correct 6 ms 12068 KB Output is correct
58 Correct 8 ms 12112 KB Output is correct
59 Correct 291 ms 39488 KB Output is correct
60 Correct 318 ms 42624 KB Output is correct
61 Correct 6 ms 12072 KB Output is correct
62 Correct 7 ms 12052 KB Output is correct
63 Correct 206 ms 37048 KB Output is correct
64 Correct 9 ms 16084 KB Output is correct
65 Correct 21 ms 27356 KB Output is correct
66 Correct 189 ms 154252 KB Output is correct
67 Correct 546 ms 248048 KB Output is correct
68 Correct 563 ms 252288 KB Output is correct
69 Correct 10 ms 13072 KB Output is correct
70 Correct 56 ms 23136 KB Output is correct
71 Correct 213 ms 47884 KB Output is correct
72 Correct 216 ms 46504 KB Output is correct
73 Correct 55 ms 20180 KB Output is correct
74 Correct 311 ms 41596 KB Output is correct
75 Correct 21 ms 15812 KB Output is correct
76 Correct 195 ms 47156 KB Output is correct
77 Correct 198 ms 47060 KB Output is correct
78 Correct 34 ms 30696 KB Output is correct
79 Correct 545 ms 218952 KB Output is correct
80 Correct 7 ms 12372 KB Output is correct
81 Correct 65 ms 22632 KB Output is correct
82 Correct 270 ms 44884 KB Output is correct
83 Correct 322 ms 41496 KB Output is correct
84 Correct 337 ms 41580 KB Output is correct
85 Correct 378 ms 41548 KB Output is correct
86 Correct 295 ms 42632 KB Output is correct
87 Correct 304 ms 42688 KB Output is correct