Submission #1279601

#	Time	Username	Problem	Language	Result	Execution time	Memory
1279601		icebear	Capital City (JOI20_capital_city)	C++20	1 / 100	2 ms	580 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 "icebear"
/*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 = 20 + 5;
int n, k;
vector<int> G[N], town[N];
int par[N][20], h[N], city[N];

struct DisjointSet {
    vector<int> lab;
    DisjointSet(int n = 0): lab(n + 5, -1) {}
    int root(int v) {
        return lab[v] < 0 ? v : lab[v] = root(lab[v]);
    }

    bool unite(int u, int v) {
        u = root(u); v = root(v);
        if (u == v) return false;
        if (h[u] > h[v]) swap(u, v);
        lab[v] = u;
        return true;
    }
} dsu;

void dfs(int u) {
    for(int v : G[u]) if (v != par[u][0]) {
        par[v][0] = u;
        h[v] = h[u] + 1;
        dfs(v);
    }
}

int LCA(int u, int v) {
    if (h[u] < h[v]) swap(u, v);
    int s = h[u] - h[v];
    RED(j, 20) if (BIT(s, j))
        u = par[u][j];
    if (u == v) return u;
    RED(j, 20) if (par[u][j] != par[v][j]) {
        u = par[u][j];
        v = par[v][j];
    }
    return par[u][0];
}

set<int> cur_city;
void connect(int u, int v) {
    int p = LCA(u, v);
    while(true) {
        u = par[dsu.root(u)][0];
        if (h[u] <= h[p]) break;
        cur_city.insert(city[u]);
        dsu.unite(u, par[u][0]);
    }

    while(true) {
        v = par[dsu.root(v)][0];
        if (h[v] <= h[p]) break;
        cur_city.insert(city[v]);
        dsu.unite(v, par[v][0]);
    }

    cur_city.insert(city[p]);
    if (p > 1) dsu.unite(p, par[p][0]);
}

int get_merge(int C) {
    dsu = DisjointSet(n);
    cur_city.clear();
    cur_city.insert(C);
    for(int X : cur_city) {
        FOR(i, 1, (int)town[X].size() - 1) FOR(j, 0, i-1) connect(town[X][j], town[X][i]);
    }
    return cur_city.size() - 1;
}

void init(void) {
    cin >> n >> k;
    FOR(i, 2, n) {
        int u, v;
        cin >> u >> v;
        G[u].pb(v);
        G[v].pb(u);
    }
    FOR(i, 1, n) {
        cin >> city[i];
        town[city[i]].pb(i);
    }
}

void process(void) {
    int ans = inf;
    REP(mask, MASK(k)) if (mask > 0) {
        dsu = DisjointSet(n);
        int cnt = 0;
        FOR(i, 1, n) for(int v : G[i])
            if (BIT(mask, city[i] - 1) && BIT(mask, city[v] - 1))
                cnt += dsu.unite(i, v);
        int sum = 0;
        FOR(i, 1, k) if (BIT(mask, i - 1)) sum += (int)town[i].size();
        if (sum - 1 == cnt) minimize(ans, __builtin_popcount(mask) - 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:144:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  144 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
capital_city.cpp:145:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  145 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 1 / 1
• Subtask 2: 0 / 10
• Subtask 3: 0 / 30
• Subtask 4: 0 / 59