Submission #752948

#	Time	Username	Problem	Language	Result	Execution time	Memory
752948		Sam_a17	Capital City (JOI20_capital_city)	C++17	100 / 100	846 ms	38956 KiB

capital_city

#define _CRT_SECURE_NO_WARNINGS
#include <bits/stdc++.h>
//#include "temp.cpp"
#include <cstdio>
using namespace std;
 
#ifndef ONLINE_JUDGE
#define dbg(x) cerr << #x <<" "; print(x); cerr << endl;
#else
#define dbg(x)
#endif
 
#define sz(x) (int((x).size()))
#define len(x) (int)x.length()
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define clr(x) (x).clear()
#define uniq(x) x.resize(unique(all(x)) - x.begin());
 
#define pb push_back
#define popf pop_front
#define popb pop_back
#define ld long double
#define ll long long
 
void print(long long t) {cerr << t;}
void print(int t) {cerr << t;}
void print(string t) {cerr << t;}
void print(char t) {cerr << t;}
void print(double t) {cerr << t;}
void print(unsigned long long t) {cerr << t;}
void print(long double t) {cerr << t;}
 
template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T> void print(T v[],T n) {cerr << "["; for(int i = 0; i < n; i++) {cerr << v[i] << " ";} cerr << "]";}
template <class T, class V> void print(pair <T, V> p) {cerr << "{"; print(p.first); cerr << ","; print(p.second); cerr << "}";}
template <class T> void print(vector <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(deque <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(set <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T> void print(multiset <T> v) {cerr << "[ "; for (T i : v) {print(i); cerr << " ";} cerr << "]";}
template <class T, class V> void print(map <T, V> v) {cerr << "[ "; for (auto i : v) {print(i); cerr << " ";} cerr << "]";}
 
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
#define nl '\n'
 
// for random generations
mt19937 myrand(chrono::steady_clock::now().time_since_epoch().count());
// mt19937 myrand(131);
 
// for grid problems
int dx[8] = {-1,0,1,0,1,-1,1,-1};
int dy[8] = {0,1,0,-1,1,1,-1,-1};
 
long long ka() {
	long long x = 0;
	bool z = false;
	while (1)
	{
		char y = getchar();
		if (y == '-')
			z = true;
		else if ('0' <= y && y <= '9')
			x = x * 10 + y - '0';
		else
		{
			if (z)
				x *= -1;
			return x;
		}
	}
}
 
// lowest / (1 << 17) >= 1e5 / (1 << 18) >= 2e5 / (1 << 21) >= 1e6
void fastIO() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr); cout.tie(nullptr);
}
// file in/out
void setIO(string str = "") {
  fastIO();
 
  if (str != "") {
    freopen((str + ".in").c_str(), "r", stdin);
    freopen((str + ".out").c_str(), "w", stdout);
  }
}
 
// Indexed Set
template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
const int N = 2e5 + 10;
vector<int> adj[N], qq[N];
bool used[N], vis[N], used_color[N];
int n, k, ans, compSize, cc[N];
int cnt_color[N], sz[N];
vector<int> use;
queue<int> q, qu;
 
int p[N];
 
void dfs(int node, int parent, bool flag) {
  sz[node] = 1;
  p[node] = parent;
  
  if(flag) {
    compSize++;
    cnt_color[cc[node]]++;
    if(cnt_color[cc[node]] == 1) {
      use.push_back(cc[node]);
    }
  }

  for(auto i: adj[node]) {
    if(i == parent || used[i]) continue;
    dfs(i, node, flag);
    sz[node] += sz[i];
  }
}

int get_centroid(int node, int parent) {
  for(auto i: adj[node]) {
    if(i == parent || used[i]) continue;
    if(sz[i] * 2 > compSize) {
      return get_centroid(i, node);
    }
  }
  return node;
}

int centroid(int u) {
  compSize = 0;
  dfs(u, 0, true);
  int pp = get_centroid(u, 0);
  dfs(pp, 0, false);
  return pp;
}

bool valid(int color) {
  return cnt_color[color] == sz(qq[color]);
}

int curr, ok = 1;
void add_group(int group) {
  if(!valid(group)) {
    ok = 0;
    return;
  }

  curr++;
  for(auto i: qq[group]) {
    if(!vis[i]) {
      qu.push(i);
    }
  }
  used_color[group] = true;
}

vector<int> nodes;

void go_up(int node) {
  if(vis[node]) {
    return;
  } else if(!used_color[cc[node]]) {
    add_group(cc[node]);
  }
  nodes.push_back(node);
  vis[node] = true;
  node = p[node];
  go_up(node);
}



void centroid_depomposition() {
  queue<int> q;
  q.push(1);

  while(!q.empty()) {
    auto u = q.front();
    q.pop();

    int centr = centroid(u);

    if(valid(cc[centr])) {
      curr = 0, ok = 1;
      
      vis[centr] = true;
      nodes.push_back(centr);
      add_group(cc[centr]);
      
      while(!qu.empty()) {
        auto u = qu.front();
        qu.pop();
        if(!valid(cc[u])) {
          ok = 0;
          break;
        }
        go_up(u);
      }

      while(!qu.empty()) qu.pop();

      if(ok) {
        ans = min(ans, curr - 1);
      }
    }

    for(auto i: use) {
      cnt_color[i] = 0;
      used_color[i] = 0;
    } 
    for(auto i: nodes) {
      vis[i] = false;
    }
    nodes.clear();
    use.clear();

    used[centr] = true;
    for(auto i: adj[centr]) {
      if(used[i]) continue;
      q.push(i);
    }
  }
}
 
void solve_() {
  cin >> n >> k;
 
  for(int i = 1; i <= n - 1; i++) {
    int a, b; cin >> a >> b;
    adj[a].push_back(b);
    adj[b].push_back(a);
  }
 
  for(int i = 1; i <= n; i++) {
    int c; cin >> c;
    cc[i] = c;
    qq[c].push_back(i);
  }

  ans = k - 1;
  centroid_depomposition();
 
  cout << ans << '\n';
}
 
int main() {
  setIO();
  
  auto solve = [&](int test_case)-> void {
    while(test_case--) {
      solve_();
    }
  };
 
  int test_cases = 1; 
  // cin >> test_cases;
  solve(test_cases);
 
  return 0;
}

Compilation message (stderr)

capital_city.cpp: In function 'void setIO(std::string)':
capital_city.cpp:88:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   88 |     freopen((str + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
capital_city.cpp:89:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   89 |     freopen((str + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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