oj.uz

답안 #525857

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
525857 2022-02-13T03:58:18 Z koioi.org-koosaga Mountains and Valleys (CCO20_day1problem3) C++17
3 / 25
 760 ms 25420 KB 
#include <bits/stdc++.h>
#define sz(v) ((int)(v).size())
#define all(v) (v).begin(), (v).end()
using namespace std;
typedef long long lint;
typedef pair<lint, lint> pi;
const int MAXN = 500005;

struct edge{
	int s, e, x;
};

int n, m;
vector<int> gph[MAXN];
int par[20][MAXN], dep[MAXN];

int lca(int x, int y){
	if(dep[x] > dep[y]) swap(x, y);
	int dx = dep[y] - dep[x];
	for(int i = 0; dx; i++){
		if(dx & 1) y = par[i][y];
		dx >>= 1;
	}
	for(int i = 19; i >= 0; i--){
		if(par[i][x] != par[i][y]){
			x = par[i][x];
			y = par[i][y];
		}
	}
	if(x != y) return par[0][x];
	return x;
}

vector<int> ord;
int din[MAXN], dout[MAXN], piv;
int f[MAXN], far[MAXN], diam[MAXN], pfar[MAXN];
vector<pi> fars[MAXN];

bool in(int u, int v){
	return din[u] <= din[v] && dout[v] <= dout[u];
}

void dfs(int x, int p = -1){
	ord.push_back(x);
	din[x] = ++piv;
	for(auto &y : gph[x]){
		if(y == p) continue;
		par[0][y] = x;
		dep[y] = dep[x] + 1;
		dfs(y, x);
	}
	dout[x] = piv;
}

bool vis[MAXN];

pi dfsl(int x, int p = -1){
	pi ret(0, x);
	for(auto &y : gph[x]){
		if(y == p || vis[y]) continue;
		auto ans = dfsl(y, x);
		ans.first++;
		ret = max(ret, ans);
	}
	return ret;
}

int main(){
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
	cin >> n >> m;
	vector<edge> qry;
	for(int i = 0; i < m; i++){
		int s, e, x; cin >> s >> e >> x;
		if(x == 1){
			gph[s].push_back(e);
			gph[e].push_back(s);
		}
		else{
			qry.push_back({s, e, x});
		}
	}
	dfs(0);
	for(int i = 1; i < 20; i++){
		for(int j = 0; j < n; j++){
			par[i][j] = par[i-1][par[i-1][j]];
		}
	}
	{
		for(int i = 0; i < n; i++){
			if(dep[i] >= 2){
				vis[i] = 1;
				vis[par[1][i]] = 1;
				f[i] = dfsl(dfsl(par[0][i]).second).first;
				vis[i] = 0;
				vis[par[1][i]] = 0;
			}
		}
		reverse(all(ord));
		for(auto &i : ord){
			for(auto &j : gph[i]){
				if(j == par[0][i]) continue;
				far[i] = max(far[i], far[j] + 1);
				diam[i] = max({diam[i], diam[j], far[j] + 1});
				fars[i].emplace_back(far[j], j);
			}
			sort(all(fars[i]));
			reverse(all(fars[i]));
			if(sz(fars[i]) >= 2) diam[i] = max(diam[i], (int)fars[i][0].first + (int)fars[i][1].first + 2);
		}
		reverse(all(ord));
		for(auto &i : ord){
			if(i == 0) continue;
			int cnt = 0;
			for(auto &j : fars[par[0][i]]){
				if(j.second == i) continue;
				cnt++;
				pfar[i] += j.first + 1;
				if(cnt == 2) break;
			}
			fars[i].emplace_back(pfar[i], par[0][i]);
			sort(all(fars[i]));
			reverse(all(fars[i]));
		}
	}
	int ans = 2 * n - 2 - diam[0];
	for(auto &x : qry){
		int l = lca(x.s, x.e);
		vector<int> v, w;
		for(int i = x.s; i != l; i = par[0][i]) v.push_back(i);
		for(int i = x.e; i != l; i = par[0][i]) w.push_back(i);
		reverse(all(w));
		v.push_back(l);
		for(auto &i : w) v.push_back(i);
		for(auto &i : v) vis[i] = 1;
		vector<int> val;
		vector<int> ndiam;
		int maxPath = -1e9;
		for(int i = x.s; dep[i] >= dep[l] + 2; i = par[0][i]) maxPath = max(maxPath, f[i] - 3 + sz(v));
		for(int i = x.e; dep[i] >= dep[l] + 2; i = par[0][i]) maxPath = max(maxPath, f[i] - 3 + sz(v));
		if(l != x.s){
			maxPath = max(maxPath, diam[x.s] - 3 + sz(v));
		}
		if(l != x.e){
			maxPath = max(maxPath, diam[x.e] - 3 + sz(v));
		}
		{
			int new_diam = 0;
			int cnt = 0;
			for(auto &[d, v] : fars[l]){
				if(in(v, x.s) || in(v, x.e)) continue;
				new_diam += d + 1;
				cnt += 1;
				if(cnt == 2) break;
			}
			maxPath = max(maxPath, new_diam - 3 + sz(v));
		}
		for(auto &i : v){
			vis[i] = 0;
			val.push_back(dfsl(i).first);
			vis[i] = 1;
		}
		for(auto &i : v) vis[i] = 0;
		int pmax = -1e9;
		for(int i = 0; i < sz(val); i++){
			maxPath = max(maxPath, sz(val) - 1 - i + val[i] + pmax);
			pmax = max(pmax, i + val[i]);
		}
		ans = min(ans, 2 * n - 4 + x.x - maxPath);
	}
	cout << ans << endl;
}

Subtask #1
1.0 / 1.0

# 결과 실행 시간 메모리 Grader output
1 Correct 11 ms 23884 KB Output is correct
2 Correct 11 ms 24012 KB Output is correct
3 Correct 11 ms 24012 KB Output is correct
4 Correct 11 ms 24012 KB Output is correct
5 Correct 11 ms 23884 KB Output is correct
6 Correct 11 ms 23912 KB Output is correct
7 Correct 12 ms 23900 KB Output is correct
8 Correct 10 ms 24012 KB Output is correct
9 Correct 11 ms 23936 KB Output is correct
10 Correct 11 ms 24012 KB Output is correct
11 Correct 12 ms 23884 KB Output is correct
12 Correct 11 ms 24016 KB Output is correct
13 Correct 11 ms 23996 KB Output is correct
14 Correct 11 ms 24012 KB Output is correct
15 Correct 12 ms 24012 KB Output is correct

Subtask #2
0.0 / 2.0

# 결과 실행 시간 메모리 Grader output
1 Correct 11 ms 23884 KB Output is correct
2 Correct 11 ms 24012 KB Output is correct
3 Correct 11 ms 24012 KB Output is correct
4 Correct 11 ms 24012 KB Output is correct
5 Correct 11 ms 23884 KB Output is correct
6 Correct 11 ms 23912 KB Output is correct
7 Correct 12 ms 23900 KB Output is correct
8 Correct 10 ms 24012 KB Output is correct
9 Correct 11 ms 23936 KB Output is correct
10 Correct 11 ms 24012 KB Output is correct
11 Correct 12 ms 23884 KB Output is correct
12 Correct 11 ms 24016 KB Output is correct
13 Correct 11 ms 23996 KB Output is correct
14 Correct 11 ms 24012 KB Output is correct
15 Correct 12 ms 24012 KB Output is correct
16 Correct 11 ms 23908 KB Output is correct
17 Correct 11 ms 24012 KB Output is correct
18 Incorrect 11 ms 24012 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #3
2.0 / 2.0

# 결과 실행 시간 메모리 Grader output
1 Correct 621 ms 25348 KB Output is correct
2 Correct 629 ms 25420 KB Output is correct
3 Correct 614 ms 25284 KB Output is correct
4 Correct 568 ms 25164 KB Output is correct
5 Correct 573 ms 25284 KB Output is correct
6 Correct 365 ms 24992 KB Output is correct
7 Correct 626 ms 25416 KB Output is correct
8 Correct 760 ms 25396 KB Output is correct
9 Correct 677 ms 25412 KB Output is correct
10 Correct 578 ms 25284 KB Output is correct
11 Correct 575 ms 25292 KB Output is correct
12 Correct 647 ms 25224 KB Output is correct
13 Correct 587 ms 25408 KB Output is correct
14 Correct 579 ms 25244 KB Output is correct

Subtask #4
0.0 / 6.0

# 결과 실행 시간 메모리 Grader output
1 Correct 11 ms 23884 KB Output is correct
2 Correct 11 ms 24012 KB Output is correct
3 Correct 11 ms 24012 KB Output is correct
4 Correct 11 ms 24012 KB Output is correct
5 Correct 11 ms 23884 KB Output is correct
6 Correct 11 ms 23912 KB Output is correct
7 Correct 12 ms 23900 KB Output is correct
8 Correct 10 ms 24012 KB Output is correct
9 Correct 11 ms 23936 KB Output is correct
10 Correct 11 ms 24012 KB Output is correct
11 Correct 12 ms 23884 KB Output is correct
12 Correct 11 ms 24016 KB Output is correct
13 Correct 11 ms 23996 KB Output is correct
14 Correct 11 ms 24012 KB Output is correct
15 Correct 12 ms 24012 KB Output is correct
16 Correct 11 ms 23908 KB Output is correct
17 Correct 11 ms 24012 KB Output is correct
18 Incorrect 11 ms 24012 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #5
0.0 / 2.0

# 결과 실행 시간 메모리 Grader output
1 Correct 11 ms 23884 KB Output is correct
2 Correct 11 ms 24012 KB Output is correct
3 Correct 11 ms 24012 KB Output is correct
4 Correct 11 ms 24012 KB Output is correct
5 Correct 11 ms 23884 KB Output is correct
6 Correct 11 ms 23912 KB Output is correct
7 Correct 12 ms 23900 KB Output is correct
8 Correct 10 ms 24012 KB Output is correct
9 Correct 11 ms 23936 KB Output is correct
10 Correct 11 ms 24012 KB Output is correct
11 Correct 12 ms 23884 KB Output is correct
12 Correct 11 ms 24016 KB Output is correct
13 Correct 11 ms 23996 KB Output is correct
14 Correct 11 ms 24012 KB Output is correct
15 Correct 12 ms 24012 KB Output is correct
16 Correct 11 ms 23908 KB Output is correct
17 Correct 11 ms 24012 KB Output is correct
18 Incorrect 11 ms 24012 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #6
0.0 / 3.0

# 결과 실행 시간 메모리 Grader output
1 Correct 11 ms 23884 KB Output is correct
2 Correct 11 ms 24012 KB Output is correct
3 Correct 11 ms 24012 KB Output is correct
4 Correct 11 ms 24012 KB Output is correct
5 Correct 11 ms 23884 KB Output is correct
6 Correct 11 ms 23912 KB Output is correct
7 Correct 12 ms 23900 KB Output is correct
8 Correct 10 ms 24012 KB Output is correct
9 Correct 11 ms 23936 KB Output is correct
10 Correct 11 ms 24012 KB Output is correct
11 Correct 12 ms 23884 KB Output is correct
12 Correct 11 ms 24016 KB Output is correct
13 Correct 11 ms 23996 KB Output is correct
14 Correct 11 ms 24012 KB Output is correct
15 Correct 12 ms 24012 KB Output is correct
16 Correct 11 ms 23908 KB Output is correct
17 Correct 11 ms 24012 KB Output is correct
18 Incorrect 11 ms 24012 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #7
0.0 / 5.0

# 결과 실행 시간 메모리 Grader output
1 Correct 11 ms 23884 KB Output is correct
2 Correct 11 ms 24012 KB Output is correct
3 Correct 11 ms 24012 KB Output is correct
4 Correct 11 ms 24012 KB Output is correct
5 Correct 11 ms 23884 KB Output is correct
6 Correct 11 ms 23912 KB Output is correct
7 Correct 12 ms 23900 KB Output is correct
8 Correct 10 ms 24012 KB Output is correct
9 Correct 11 ms 23936 KB Output is correct
10 Correct 11 ms 24012 KB Output is correct
11 Correct 12 ms 23884 KB Output is correct
12 Correct 11 ms 24016 KB Output is correct
13 Correct 11 ms 23996 KB Output is correct
14 Correct 11 ms 24012 KB Output is correct
15 Correct 12 ms 24012 KB Output is correct
16 Correct 11 ms 23908 KB Output is correct
17 Correct 11 ms 24012 KB Output is correct
18 Incorrect 11 ms 24012 KB Output isn't correct
19 Halted 0 ms 0 KB -

Subtask #8
0.0 / 4.0

# 결과 실행 시간 메모리 Grader output
1 Correct 11 ms 23884 KB Output is correct
2 Correct 11 ms 24012 KB Output is correct
3 Correct 11 ms 24012 KB Output is correct
4 Correct 11 ms 24012 KB Output is correct
5 Correct 11 ms 23884 KB Output is correct
6 Correct 11 ms 23912 KB Output is correct
7 Correct 12 ms 23900 KB Output is correct
8 Correct 10 ms 24012 KB Output is correct
9 Correct 11 ms 23936 KB Output is correct
10 Correct 11 ms 24012 KB Output is correct
11 Correct 12 ms 23884 KB Output is correct
12 Correct 11 ms 24016 KB Output is correct
13 Correct 11 ms 23996 KB Output is correct
14 Correct 11 ms 24012 KB Output is correct
15 Correct 12 ms 24012 KB Output is correct
16 Correct 11 ms 23908 KB Output is correct
17 Correct 11 ms 24012 KB Output is correct
18 Incorrect 11 ms 24012 KB Output isn't correct
19 Halted 0 ms 0 KB -