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답안 #538150

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
538150 2022-03-16T06:26:30 Z Haruto810198 수도 (JOI20_capital_city) C++17
11 / 100
 706 ms 177204 KB 
#include <bits/stdc++.h>
 
using namespace std;
 
#define int long long
#define double long double
 
#define FOR(i, l, r, d) for(int i=(l); i<=(r); i+=(d))
#define szof(x) ((int)(x).size())
 
#define vi vector<int>
#define pii pair<int, int>
 
#define F first
#define S second
 
#define pb push_back
#define eb emplace_back
#define mkp make_pair

const int INF = INT_MAX;
const int LNF = INF*INF;
const int MOD = 1000000007;
const double eps = 1e-12;
 
//#pragma GCC optimize("Ofast")
//#pragma GCC optimize("unroll-loops")

const int MAX = 200010;

int n, k;
vi edge_t[MAX];
int city[MAX];

vi occ[MAX];

int res;

// HLD
int par[MAX], sz[MAX], dep[MAX], heavy[MAX], dfn[MAX], fr[MAX];
int ts;

// segment tree optimization
#define V st[cidx]

struct Node{
	int lc, rc;
	int sl, sr;
};
int nodes = 1;
Node st[2*MAX];
int leaf[MAX]; // leaf[i] = id. of node [i, i] in st
int w[MAX];

// SCC
vi edge_g[2*MAX];
vi edge_g_rev[2*MAX];
vi dfstk;
vi cur_scc;
bool vis[2*MAX];
int scccnt;
int sccid[2*MAX];
vi edge_scc[2*MAX];
int scc_sz[2*MAX];

// ===============================================================

// HLD
void find_heavy(int v, int pv){
	par[v] = pv;
	sz[v] = 1;
	if(v == pv) dep[v] = 0;
	else dep[v] = dep[pv] + 1;
	
	int Max = 0;
	heavy[v] = -1;
	for(int i : edge_t[v]){
		if(i == pv) continue;
		find_heavy(i, v);
		sz[v] += sz[i];
		if(Max < sz[i]){
			Max = sz[i];
			heavy[v] = i;
		}
	}
}

void HLD(int v, int pv, int frv){
	dfn[v] = ++ts;
	fr[v] = frv;
	
	if(heavy[v] != -1) HLD(heavy[v], v, frv);

	for(int i : edge_t[v]){
		if(i == pv or i == heavy[v]) continue;
		HLD(i, v, i);
	}
}

vector<pii> Segs(int u, int v){
	vector<pii> ret;
	while(fr[u] != fr[v]){
		if(dep[fr[u]] > dep[fr[v]]) swap(u, v);
		ret.eb(dfn[fr[v]], dfn[v]);
		v = par[fr[v]];
	}

	if(dep[u] > dep[v]) swap(u, v);
	ret.eb(dfn[u], dfn[v]);

	return ret;
}

// segment tree
void build(int cidx, int cl, int cr){
	V.sl = cl;
	V.sr = cr;
	if(cl < cr){
		int mid = (cl + cr) / 2;
		
		V.lc = ++nodes;
		edge_g[cidx].pb(V.lc);
		build(nodes, cl, mid);

		V.rc = ++nodes;
		edge_g[cidx].pb(V.rc);
		build(nodes, mid+1, cr);
	}
	else{
		leaf[cl] = cidx;
	}
}

void add_edge(int cidx, int ml, int mr, int from){
	//if(cidx == 1) cerr<<"add_edge "<<from<<" -> ["<<ml<<", "<<mr<<"] "<<endl;
	// ml, mr, from : dfn of nodes
	if(mr < V.sl or V.sr < ml) return;
	if(ml <= V.sl and V.sr <= mr){
		edge_g[leaf[from]].pb(cidx);
		return;
	}

	add_edge(V.lc, ml, mr, from);
	add_edge(V.rc, ml, mr, from);
}

// SCC
void dfs1(int v){
	vis[v] = 1;
	for(int i : edge_g[v]){
		if(vis[i] == 0) dfs1(i);
	}
	dfstk.pb(v);
}

void dfs2(int v){
	vis[v] = 1;
	for(int i : edge_g_rev[v]){
		if(vis[i] == 0) dfs2(i);
	}
	cur_scc.pb(v);
}

void find_sccs(){

	FOR(v, 1, nodes, 1){
		if(vis[v] == 0) dfs1(v);
	}
	
	FOR(v, 1, nodes, 1){
		for(int i : edge_g[v]){
			edge_g_rev[i].pb(v);
		}
		vis[v] = 0;
	}
	
	while(!dfstk.empty()){
		int v = dfstk.back();
		dfstk.pop_back();

		if(vis[v] == 0){
			dfs2(v);
			scccnt++;
			for(int i : cur_scc){
				sccid[i] = scccnt;
				scc_sz[scccnt] += w[i];
			}
			cur_scc.clear();
		}
	}
	/*	
	cerr<<"sccid : ";
	FOR(v, 1, nodes, 1){
		cerr<<sccid[v]<<' ';
	}
	cerr<<endl;
	*/
	FOR(v, 1, nodes, 1){
		for(int i : edge_g[v]){
			if(sccid[v] != sccid[i]) edge_scc[sccid[v]].pb(sccid[i]);
		}
	}
	
	FOR(v, 1, scccnt, 1){
		auto it = unique(edge_scc[v].begin(), edge_scc[v].end());
		edge_scc[v].resize(distance(edge_scc[v].begin(), it));
		/*	
		cerr<<"scc_sz["<<v<<"] = "<<scc_sz[v]<<", ";
		cerr<<"edge_scc["<<v<<"] : ";
		for(int i : edge_scc[v]){
			cerr<<i<<' ';
		}
		cerr<<endl;
		*/
	}
	
	res = INF;
	FOR(v, 1, scccnt, 1){
		if(edge_scc[v].empty()) res = min(res, scc_sz[v]);
	}
}

signed main(){
	
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
	
	cin>>n>>k;
	FOR(i, 1, n-1, 1){
		int u, v;
		cin>>u>>v;
		edge_t[u].pb(v);
		edge_t[v].pb(u);
	}

	FOR(i, 1, n, 1){
		cin>>city[i];
		occ[city[i]].pb(i);
	}

	// HLD
	find_heavy(1, 1);
	HLD(1, 1, 1);
	/*	
	cerr<<"dfn : ";
	FOR(i, 1, n, 1){
		cerr<<dfn[i]<<' ';
	}
	cerr<<endl;
	*/
	// segment tree
	build(1, 1, n);
	FOR(i, 1, k, 1){
		FOR(j, 0, szof(occ[i])-2, 1){
			int u = occ[i][j], v = occ[i][j+1]; // u, v = id. of nodes
			vector<pii> segs = Segs(u, v);
			for(pii p : segs){
				add_edge(1, p.F, p.S, dfn[u]);
			}
			add_edge(1, dfn[u], dfn[u], dfn[v]);
		}
	}
	
	// w
	FOR(i, 1, k, 1){
		int v = occ[i].front();
		w[leaf[dfn[v]]] = 1;
	}

	// SCC
	find_sccs();
	
	cout<<res - 1<<'\n';
	
	return 0;
	
}

Subtask #1
1.0 / 1.0

# 결과 실행 시간 메모리 Grader output
1 Correct 22 ms 37972 KB Output is correct
2 Correct 22 ms 37924 KB Output is correct
3 Correct 23 ms 37920 KB Output is correct
4 Correct 20 ms 37972 KB Output is correct
5 Correct 20 ms 37972 KB Output is correct
6 Correct 20 ms 37964 KB Output is correct
7 Correct 22 ms 37908 KB Output is correct
8 Correct 21 ms 37960 KB Output is correct
9 Correct 21 ms 37976 KB Output is correct
10 Correct 22 ms 37972 KB Output is correct

Subtask #2
10.0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 22 ms 37972 KB Output is correct
2 Correct 22 ms 37924 KB Output is correct
3 Correct 23 ms 37920 KB Output is correct
4 Correct 20 ms 37972 KB Output is correct
5 Correct 20 ms 37972 KB Output is correct
6 Correct 20 ms 37964 KB Output is correct
7 Correct 22 ms 37908 KB Output is correct
8 Correct 21 ms 37960 KB Output is correct
9 Correct 21 ms 37976 KB Output is correct
10 Correct 22 ms 37972 KB Output is correct
11 Correct 31 ms 39128 KB Output is correct
12 Correct 28 ms 39108 KB Output is correct
13 Correct 26 ms 39180 KB Output is correct
14 Correct 26 ms 39068 KB Output is correct
15 Correct 26 ms 39036 KB Output is correct
16 Correct 25 ms 39096 KB Output is correct
17 Correct 24 ms 39008 KB Output is correct
18 Correct 25 ms 39092 KB Output is correct
19 Correct 27 ms 39116 KB Output is correct
20 Correct 32 ms 38988 KB Output is correct
21 Correct 29 ms 39108 KB Output is correct
22 Correct 24 ms 39096 KB Output is correct
23 Correct 24 ms 39220 KB Output is correct
24 Correct 23 ms 38892 KB Output is correct
25 Correct 23 ms 38996 KB Output is correct
26 Correct 24 ms 39028 KB Output is correct
27 Correct 25 ms 38996 KB Output is correct
28 Correct 26 ms 38996 KB Output is correct
29 Correct 29 ms 38996 KB Output is correct
30 Correct 26 ms 39004 KB Output is correct

Subtask #3
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Incorrect 706 ms 177204 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 59.0

# 결과 실행 시간 메모리 Grader output
1 Correct 22 ms 37972 KB Output is correct
2 Correct 22 ms 37924 KB Output is correct
3 Correct 23 ms 37920 KB Output is correct
4 Correct 20 ms 37972 KB Output is correct
5 Correct 20 ms 37972 KB Output is correct
6 Correct 20 ms 37964 KB Output is correct
7 Correct 22 ms 37908 KB Output is correct
8 Correct 21 ms 37960 KB Output is correct
9 Correct 21 ms 37976 KB Output is correct
10 Correct 22 ms 37972 KB Output is correct
11 Correct 31 ms 39128 KB Output is correct
12 Correct 28 ms 39108 KB Output is correct
13 Correct 26 ms 39180 KB Output is correct
14 Correct 26 ms 39068 KB Output is correct
15 Correct 26 ms 39036 KB Output is correct
16 Correct 25 ms 39096 KB Output is correct
17 Correct 24 ms 39008 KB Output is correct
18 Correct 25 ms 39092 KB Output is correct
19 Correct 27 ms 39116 KB Output is correct
20 Correct 32 ms 38988 KB Output is correct
21 Correct 29 ms 39108 KB Output is correct
22 Correct 24 ms 39096 KB Output is correct
23 Correct 24 ms 39220 KB Output is correct
24 Correct 23 ms 38892 KB Output is correct
25 Correct 23 ms 38996 KB Output is correct
26 Correct 24 ms 39028 KB Output is correct
27 Correct 25 ms 38996 KB Output is correct
28 Correct 26 ms 38996 KB Output is correct
29 Correct 29 ms 38996 KB Output is correct
30 Correct 26 ms 39004 KB Output is correct
31 Incorrect 706 ms 177204 KB Output isn't correct
32 Halted 0 ms 0 KB -