Submission #1279641

#	Time	Username	Problem	Language	Result	Execution time	Memory
1279641		icebear	수도 (JOI20_capital_city)	C++20	100 / 100	501 ms	33352 KiB

capital_city

// ~~ icebear ~~
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;

template<class T>
    bool minimize(T &a, const T &b) {
        if (a > b) return a = b, true;
        return false;
    }

template<class T>
    bool maximize(T &a, const T &b) {
        if (a < b) return a = b, true;
        return false;
    }

#define FOR(i,a,b) for(int i=(a); i<=(b); ++i)
#define FORR(i,a,b) for(int i=(a); i>=(b); --i)
#define REP(i, n) for(int i=0; i<(n); ++i)
#define RED(i, n) for(int i=(n)-1; i>=0; --i)
#define MASK(i) (1LL << (i))
#define BIT(S, i) (((S) >> (i)) & 1)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define task "gen"
/*END OF TEMPLATE. ICEBEAR AND THE CAT WILL WIN VOI26 */

const int MOD = 1e9 + 7;
const int inf = 1e9 + 27092008;
const ll INF = 1e18 + 27092008;
const int N = 2e5 + 5;
int numNode, numCity;
vector<int> G[N], belong[N];
int sz[N], city[N], ans = inf;
bool isCentroid[N];

int get_sz(int u, int par) {
    sz[u] = 1;
    for(int v : G[u]) if (v != par && !isCentroid[v])
        sz[u] += get_sz(v, u);
    return sz[u];
}

int findCentroid(int u, int par, const int &subtree) {
    for(int v : G[u]) if (v != par && !isCentroid[v] && sz[v] * 2 > subtree)
        return findCentroid(v, u, subtree);
    return u;
}

vector<int> nodes;
int cnt[N], par[N];
bool vis[N];
void dfs(int u) {
    nodes.pb(u);
    cnt[city[u]]++;
    vis[u] = false;
    for(int v : G[u]) if (v != par[u] && !isCentroid[v]) {
        par[v] = u;
        dfs(v);
    }
}

bool haveAll(int city) {
    return cnt[city] == (int)belong[city].size();
}

void buildCentroid(int u) {
    int centroid = findCentroid(u, -1, get_sz(u, -1));
    isCentroid[centroid] = true;
    par[centroid] = -1;
    dfs(centroid);

    if (haveAll(city[centroid])) {
        queue<int> q;
        int unite = 0;
        for(int v : belong[city[centroid]]) {
            q.push(v);
            vis[v] = true;
        }
        while(!q.empty()) {
            int x = q.front(); q.pop();
            x = par[x];
            if (x <= 0) continue;
            while(!vis[x]) {
                if (haveAll(city[x]) == false) {
                    unite = inf;
                    break;
                }
                vis[x] = true;
                for(int v : belong[city[x]]) {
                    vis[v] = true;
                    q.push(v);
                }
                x = par[x];
                unite++;
            }
            if (unite == inf) break;
        }
        minimize(ans, unite);
    }
    
    for(int x : nodes) {
        vis[x] = true;
        cnt[city[x]]--;
    }
    nodes.clear();

    for(int v : G[centroid]) if (!isCentroid[v])
        buildCentroid(v);
}

void init(void) {
    cin >> numNode >> numCity;
    FOR(i, 2, numNode) {
        int u, v;
        cin >> u >> v;
        G[u].pb(v);
        G[v].pb(u);
    }
    FOR(i, 1, numNode) cin >> city[i], belong[city[i]].push_back(i);
}

void process(void) {
    buildCentroid(1);
    cout << ans;
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    if (fopen(task".inp", "r")) {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }
    int tc = 1;
//    cin >> tc;
    while(tc--) {
        init();
        process();
    }
    return 0;
}

Compilation message (stderr)

capital_city.cpp: In function 'int main()':
capital_city.cpp:139:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  139 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
capital_city.cpp:140:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  140 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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