Submission #554742

#	Time	Username	Problem	Language	Result	Execution time	Memory
554742		keta_tsimakuridze	Capital City (JOI20_capital_city)	C++17	100 / 100	1004 ms	46348 KiB

capital_city

#include<bits/stdc++.h>
using namespace std;
#define int long long
#define pii pair<int,int>
#define f first
#define s second
#define endl "\n"
const int N = 2e5 + 5, mod = 1e9 + 7; //!
int t, sz[N], f[N], n, vis[N], c[N], ans, p[N], col[N];
int cnt[N];
vector<int> rem, x[N];
vector<int> V[N];
queue<int> q;
void dfs0(int u,int p) {
	sz[u] = 1;
	for(int i = 0; i < V[u].size(); i++) {
		if(V[u][i] == p || f[V[u][i]]) continue;
		dfs0(V[u][i], u);
		sz[u] += sz[V[u][i]];
	}
}
int find(int u, int p, int SZ) {
	for(int i = 0; i < V[u].size(); i++) {
		if(V[u][i] == p || f[V[u][i]]) continue;
		if(sz[V[u][i]] > SZ / 2) return find(V[u][i], u, SZ);
	}
	return u;
}
void dfs(int u,int C) {
	rem.push_back(c[u]);
	x[c[u]].push_back(u);
	for(int i = 0; i < V[u].size(); i++) {
		if(V[u][i] == p[u] || f[V[u][i]]) continue;
		p[V[u][i]] = u;
		dfs(V[u][i], C);
	}
}
void decompose(int U) {
	dfs0(U, 0);
	int C = find(U, 0, sz[U]);
	p[C] = 0;
	dfs(C, C);
	int cn = 0; 
	q.push(C);
	
	while(q.size()) {
		int u = q.front();
		q.pop();
		if(cnt[c[u]] != x[c[u]].size()) cn = n;
		if(vis[u] == C) continue;
		if(col[c[u]] != C) { 
			cn++;
			for(int j = 0; j < x[c[u]].size(); j++) {
				q.push(x[c[u]][j]);
			}
		}
		col[c[u]] = C; vis[u] = C;
		if(p[u]) q.push(p[u]); 
	}
	while(rem.size()) x[rem.back()].clear(), rem.pop_back();
	ans = min(ans, cn);
	f[C] = 1;
	for(int i = 0; i < V[C].size(); i++) {
		if(!f[V[C][i]]) decompose(V[C][i]);
	}
}
main() {
	ios_base::sync_with_stdio(false),cin.tie(0),cout.tie(0);
	int k;
	cin >> n >> k;
	for(int i = 2; i <= n; i++) {
		int u, v;
		cin >> u >> v;
		V[u].push_back(v);
		V[v].push_back(u);
	}
	
	for(int i = 1; i <= n; i++) cin >> c[i], cnt[c[i]]++;
	ans = k;
	decompose(1);
	cout << --ans;
}

Compilation message (stderr)

capital_city.cpp: In function 'void dfs0(long long int, long long int)':
capital_city.cpp:16:19: 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]
   16 |  for(int i = 0; i < V[u].size(); i++) {
      |                 ~~^~~~~~~~~~~~~
capital_city.cpp: In function 'long long int find(long long int, long long int, long long int)':
capital_city.cpp:23:19: 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]
   23 |  for(int i = 0; i < V[u].size(); i++) {
      |                 ~~^~~~~~~~~~~~~
capital_city.cpp: In function 'void dfs(long long int, long long int)':
capital_city.cpp:32:19: 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]
   32 |  for(int i = 0; i < V[u].size(); i++) {
      |                 ~~^~~~~~~~~~~~~
capital_city.cpp: In function 'void decompose(long long int)':
capital_city.cpp:49:16: 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]
   49 |   if(cnt[c[u]] != x[c[u]].size()) cn = n;
      |      ~~~~~~~~~~^~~~~~~~~~~~~~~~~
capital_city.cpp:53:21: 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]
   53 |    for(int j = 0; j < x[c[u]].size(); j++) {
      |                   ~~^~~~~~~~~~~~~~~~
capital_city.cpp:63:19: 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]
   63 |  for(int i = 0; i < V[C].size(); i++) {
      |                 ~~^~~~~~~~~~~~~
capital_city.cpp: At global scope:
capital_city.cpp:67:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   67 | main() {
      | ^~~~

• Subtask 1: 1 / 1
• Subtask 2: 10 / 10
• Subtask 3: 30 / 30
• Subtask 4: 59 / 59