oj.uz

Submission #931790

# Submission time Handle Problem Language Result Execution time Memory
931790 2024-02-22T10:56:11 Z vjudge1 Network (BOI15_net) C++17
63 / 100
 314 ms 51632 KB 
// in the name of God
#include<bits/stdc++.h>
using namespace std;
#define int long long
#define fast() ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define ff first
#define ss second
#define pb(x) push_back(x)
#define all(x) x.begin(), x.end()
#define mk make_pair
#define ppb pop_back
#define endl '\n'
#define pii pair<int, int>
#define sz(x) (int)x.size()
#define file() freopen("input.txt", "r", stdin);
#pragma GCC optimize("Ofast")
#pragma GCC optimize("O4")
#pragma GCC optimize("unroll-loops")
//#pragma GCC target("avx2")
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int mod = 1e9 + 7, maxn = 2e3 + 10, sq = 3163, inf = 1e18 + 10, lg = 25, pp = 4447, modd = 1e9 + 9;

int n;
vector<vector<int>> g(maxn), par(lg, vector<int> (maxn, -1));
int h[maxn], mark[maxn];

void dfs(int u = 0, int parr = -1){
	par[0][u] = parr;
	for(int i = 1; i < lg; ++i){
		if(par[i - 1][u] < 0) break;
		par[i][u] = par[i - 1][par[i - 1][u]];
	}
	for(int v : g[u]){
		if(v != parr){
			h[v] = h[u] + 1;
			dfs(v, u);
		}
	}
}
int lca(int a, int b){
	if(h[a] < h[b]) swap(a, b);
	for(int i = lg - 1; i >= 0; --i){
		if(par[i][a] > -1 && h[par[i][a]] >= h[b]) a = par[i][a];
	}
	if(a == b) return a;
	for(int i = lg - 1; i >= 0; --i){
		if(par[i][a] > -1 && par[i][b] > -1 && par[i][a] != par[i][b]){
			a = par[i][a];
			b = par[i][b];
		}
	}
	return par[0][a];
}
signed main(){
	fast();//file();
	cin >> n;
	for(int i = 1; i < n; ++i){
		int u, v; cin >> u >> v;
		u--; v--;
		g[u].pb(v);
		g[v].pb(u);
	}
	dfs();
	vector<int> b;
	vector<pair<int, pii>> a;
	for(int i = 0; i < n; ++i) if(g[i].size() == 1) b.pb(i);
	for(int i = 0; i < b.size(); ++i){
		for(int j = i + 1; j < b.size(); ++j){
			int x = h[b[i]] + h[b[j]] - 2 * h[lca(b[i], b[j])];
			a.pb(mk(x, mk(b[i], b[j])));
		}
	}
	cout << ceil((double) b.size() / 2) << endl;
	sort(all(a));
	reverse(all(a));
	for(int i = 0; i < a.size(); ++i){
		int x = a[i].ff, y = a[i].ss.ff, z = a[i].ss.ss;
		if(!mark[y] && !mark[z]){
			mark[y] = true; mark[z] = true;
			cout << y + 1 << " " << z + 1 << endl;
		}
	}
	for(int i = 0; i < b.size(); ++i){
		int mxf = -1, r = 0;
		if(!mark[b[i]]){
			for(int j = 0; j < b.size(); ++j){
				int x = h[b[i]] + h[b[j]] - 2 * h[lca(b[i], b[j])];
				if(mxf < x) {mxf = x; r = b[j];}
			}
			cout << b[i] + 1 << " " << r + 1;
			break;
		}
	}
}
// Running from the daylight...

Compilation message

net.cpp: In function 'int main()':
net.cpp:67:19: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |  for(int i = 0; i < b.size(); ++i){
      |                 ~~^~~~~~~~~~
net.cpp:68:24: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   68 |   for(int j = i + 1; j < b.size(); ++j){
      |                      ~~^~~~~~~~~~
net.cpp:76:19: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<std::pair<long long int, std::pair<long long int, long long int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   76 |  for(int i = 0; i < a.size(); ++i){
      |                 ~~^~~~~~~~~~
net.cpp:77:7: warning: unused variable 'x' [-Wunused-variable]
   77 |   int x = a[i].ff, y = a[i].ss.ff, z = a[i].ss.ss;
      |       ^
net.cpp:83:19: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   83 |  for(int i = 0; i < b.size(); ++i){
      |                 ~~^~~~~~~~~~
net.cpp:86:21: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   86 |    for(int j = 0; j < b.size(); ++j){
      |                   ~~^~~~~~~~~~

Subtask #1
18.0 / 18.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 856 KB Output is correct
2 Correct 0 ms 860 KB Output is correct
3 Correct 1 ms 860 KB Output is correct
4 Correct 0 ms 860 KB Output is correct
5 Correct 0 ms 860 KB Output is correct
6 Correct 1 ms 860 KB Output is correct
7 Correct 1 ms 860 KB Output is correct
8 Correct 1 ms 860 KB Output is correct
9 Correct 1 ms 860 KB Output is correct
10 Correct 1 ms 856 KB Output is correct
11 Correct 1 ms 856 KB Output is correct
12 Correct 1 ms 860 KB Output is correct
13 Correct 1 ms 860 KB Output is correct
14 Correct 1 ms 860 KB Output is correct
15 Correct 1 ms 860 KB Output is correct
16 Correct 0 ms 860 KB Output is correct
17 Correct 1 ms 860 KB Output is correct
18 Correct 1 ms 856 KB Output is correct
19 Correct 0 ms 860 KB Output is correct
20 Correct 0 ms 860 KB Output is correct

Subtask #2
45.0 / 45.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 856 KB Output is correct
2 Correct 0 ms 860 KB Output is correct
3 Correct 1 ms 860 KB Output is correct
4 Correct 0 ms 860 KB Output is correct
5 Correct 0 ms 860 KB Output is correct
6 Correct 1 ms 860 KB Output is correct
7 Correct 1 ms 860 KB Output is correct
8 Correct 1 ms 860 KB Output is correct
9 Correct 1 ms 860 KB Output is correct
10 Correct 1 ms 856 KB Output is correct
11 Correct 1 ms 856 KB Output is correct
12 Correct 1 ms 860 KB Output is correct
13 Correct 1 ms 860 KB Output is correct
14 Correct 1 ms 860 KB Output is correct
15 Correct 1 ms 860 KB Output is correct
16 Correct 0 ms 860 KB Output is correct
17 Correct 1 ms 860 KB Output is correct
18 Correct 1 ms 856 KB Output is correct
19 Correct 0 ms 860 KB Output is correct
20 Correct 0 ms 860 KB Output is correct
21 Correct 1 ms 860 KB Output is correct
22 Correct 282 ms 51488 KB Output is correct
23 Correct 255 ms 51632 KB Output is correct
24 Correct 314 ms 51632 KB Output is correct
25 Correct 95 ms 26832 KB Output is correct
26 Correct 62 ms 15304 KB Output is correct
27 Correct 164 ms 27324 KB Output is correct
28 Correct 155 ms 27356 KB Output is correct
29 Correct 90 ms 14284 KB Output is correct
30 Correct 1 ms 856 KB Output is correct
31 Correct 168 ms 26048 KB Output is correct
32 Correct 1 ms 860 KB Output is correct
33 Correct 0 ms 860 KB Output is correct
34 Correct 0 ms 856 KB Output is correct
35 Correct 1 ms 860 KB Output is correct
36 Correct 1 ms 860 KB Output is correct
37 Correct 1 ms 860 KB Output is correct
38 Correct 1 ms 860 KB Output is correct
39 Correct 1 ms 860 KB Output is correct
40 Correct 1 ms 860 KB Output is correct
41 Correct 1 ms 1116 KB Output is correct
42 Correct 13 ms 5584 KB Output is correct
43 Correct 60 ms 13592 KB Output is correct
44 Correct 1 ms 1112 KB Output is correct
45 Correct 4 ms 1624 KB Output is correct
46 Correct 23 ms 4052 KB Output is correct
47 Correct 0 ms 860 KB Output is correct
48 Correct 5 ms 1748 KB Output is correct
49 Correct 58 ms 14284 KB Output is correct
50 Correct 1 ms 860 KB Output is correct
51 Correct 0 ms 872 KB Output is correct
52 Correct 1 ms 860 KB Output is correct
53 Correct 13 ms 2516 KB Output is correct
54 Correct 1 ms 860 KB Output is correct
55 Correct 9 ms 2516 KB Output is correct
56 Correct 1 ms 856 KB Output is correct
57 Correct 17 ms 4816 KB Output is correct
58 Correct 312 ms 51212 KB Output is correct

Subtask #3
0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 856 KB Output is correct
2 Correct 0 ms 860 KB Output is correct
3 Correct 1 ms 860 KB Output is correct
4 Correct 0 ms 860 KB Output is correct
5 Correct 0 ms 860 KB Output is correct
6 Correct 1 ms 860 KB Output is correct
7 Correct 1 ms 860 KB Output is correct
8 Correct 1 ms 860 KB Output is correct
9 Correct 1 ms 860 KB Output is correct
10 Correct 1 ms 856 KB Output is correct
11 Correct 1 ms 856 KB Output is correct
12 Correct 1 ms 860 KB Output is correct
13 Correct 1 ms 860 KB Output is correct
14 Correct 1 ms 860 KB Output is correct
15 Correct 1 ms 860 KB Output is correct
16 Correct 0 ms 860 KB Output is correct
17 Correct 1 ms 860 KB Output is correct
18 Correct 1 ms 856 KB Output is correct
19 Correct 0 ms 860 KB Output is correct
20 Correct 0 ms 860 KB Output is correct
21 Correct 1 ms 860 KB Output is correct
22 Correct 282 ms 51488 KB Output is correct
23 Correct 255 ms 51632 KB Output is correct
24 Correct 314 ms 51632 KB Output is correct
25 Correct 95 ms 26832 KB Output is correct
26 Correct 62 ms 15304 KB Output is correct
27 Correct 164 ms 27324 KB Output is correct
28 Correct 155 ms 27356 KB Output is correct
29 Correct 90 ms 14284 KB Output is correct
30 Correct 1 ms 856 KB Output is correct
31 Correct 168 ms 26048 KB Output is correct
32 Correct 1 ms 860 KB Output is correct
33 Correct 0 ms 860 KB Output is correct
34 Correct 0 ms 856 KB Output is correct
35 Correct 1 ms 860 KB Output is correct
36 Correct 1 ms 860 KB Output is correct
37 Correct 1 ms 860 KB Output is correct
38 Correct 1 ms 860 KB Output is correct
39 Correct 1 ms 860 KB Output is correct
40 Correct 1 ms 860 KB Output is correct
41 Correct 1 ms 1116 KB Output is correct
42 Correct 13 ms 5584 KB Output is correct
43 Correct 60 ms 13592 KB Output is correct
44 Correct 1 ms 1112 KB Output is correct
45 Correct 4 ms 1624 KB Output is correct
46 Correct 23 ms 4052 KB Output is correct
47 Correct 0 ms 860 KB Output is correct
48 Correct 5 ms 1748 KB Output is correct
49 Correct 58 ms 14284 KB Output is correct
50 Correct 1 ms 860 KB Output is correct
51 Correct 0 ms 872 KB Output is correct
52 Correct 1 ms 860 KB Output is correct
53 Correct 13 ms 2516 KB Output is correct
54 Correct 1 ms 860 KB Output is correct
55 Correct 9 ms 2516 KB Output is correct
56 Correct 1 ms 856 KB Output is correct
57 Correct 17 ms 4816 KB Output is correct
58 Correct 312 ms 51212 KB Output is correct
59 Runtime error 1 ms 1368 KB Execution killed with signal 11
60 Halted 0 ms 0 KB -