Submission #1131179

#	Time	Username	Problem	Language	Result	Execution time	Memory
1131179		steveonalex	Capital City (JOI20_capital_city)	C++20	31 / 100	270 ms	50388 KiB

capital_city

#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
 
#define MASK(i) (1ULL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()
 
ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll gcd(ll a, ll b){return __gcd(a, b);}
ll lcm(ll a, ll b){return a / gcd(a, b) * b;}
 
ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ull mask){return __builtin_popcountll(mask);}
int ctz(ull mask){return __builtin_ctzll(mask);}
int logOf(ull mask){return 63 - __builtin_clzll(mask);}
 
mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}
double rngesus_d(double l, double r){
    double cur = rngesus(0, MASK(60) - 1);
    cur /= MASK(60) - 1;
    return l + cur * (r - l);
}
 
template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b) {a = b; return true;}
        return false;
    }
 
template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b) {a = b; return true;}
        return false;
    }
 
template <class T>
    void printArr(T container, string separator = " ", string finish = "\n", ostream &out = cout){
        for(auto item: container) out << item << separator;
        out << finish;
    }
 
template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }


const int N = 2e5 + 69, LOG_N = 18;
int n, k;
vector<int> graph[N];
int a[N], l[N], h[N];
int parent[N][LOG_N];
int dfs_cnt = 0;

void dfs(int u, int p){
    l[u] = ++dfs_cnt;
    h[u] = h[p] + 1;
    for(int j = 1; (int)MASK(j) < h[u]; ++j)
        parent[u][j] = parent[parent[u][j-1]][j-1];
    for(int v: graph[u]) if (v != p){
        parent[v][0] = u;
        dfs(v, u);
    }
}

int LCA(int u, int v){
    if (h[u] < h[v]) swap(u, v);
    int diff = h[u] - h[v];
    for(int j = 0; j < LOG_N; ++j) if (GETBIT(diff, j)) 
        u = parent[u][j];
    if (u == v) return u;
    for(int j = LOG_N - 1; j >= 0; --j) if (parent[u][j] != parent[v][j]){
        u = parent[u][j];
        v = parent[v][j];
    }
    return parent[u][0];
}

int sum_path(int u, int v){
    return h[u] + h[v] - 2 * h[LCA(u, v)];
}


struct DSU{
    int n;
    vector<int> parent, sz, lck;
    vector<vector<int>> S;

    DSU(int _n){
        n = _n;
        parent.resize(n+1); sz.resize(n+1, 1); 
        lck.resize(n+1); S.resize(n+1);
        for(int i = 0; i<=n; ++i) parent[i] = i;
    }

    int find_set(int u){return (u == parent[u]) ? u : (parent[u] = find_set(parent[u]));}
    bool same_set(int u, int v){return find_set(u) == find_set(v);}

    bool join_set(int u, int v){
        u = find_set(u), v = find_set(v);
        if (u != v){
            if (sz[u] < sz[v]) swap(u, v);
            parent[v] = u;
            sz[u] += sz[v];
            lck[u] = LCA(lck[u], lck[v]);
            for(int i: S[v]) S[u].push_back(i);
            return true;
        }
        return false;
    }

    int get_size(int u){return sz[find_set(u)];}
    int get_lck(int u){return lck[find_set(u)];}

    int get_top(int u){
        if (S[find_set(u)].empty()) return -1;
        int cur = S[find_set(u)].back();
        S[find_set(u)].pop_back();
        return cur;
    }

    void push_cc(int u, int v){
        S[find_set(u)].push_back(v);
    }
};

void solve(){
    cin >> n >> k;
    for(int i = 1; i<n; ++i){
        int u, v; cin >> u >> v;
        graph[u].push_back(v);
        graph[v].push_back(u);
    }

    for(int i = 1; i<=n; ++i) cin >> a[i];
    dfs(1, 0);

    vector<vector<int>> hype(k+1);
    for(int i= 1; i<=n; ++i) hype[a[i]].push_back(i);

    vector<array<int, 3>> color(k);
    for(int i = 1; i<=k; ++i){
        sort(ALL(hype[i]), [](int x, int y){return l[x] < l[y];});

        color[i-1][0] = -l[LCA(hype[i][0], hype[i].back())];
        color[i-1][1] = l[hype[i][0]];
        color[i-1][2] = i;
    }
    sort(ALL(color));

    DSU mst(k);
    for(int i = 1; i <= k; ++i){
        mst.lck[i] = LCA(hype[i][0], hype[i].back());
        for(int j: hype[i]) 
            mst.S[i].push_back(j);
    }

    int mi = 1e9 + 69;
    for(auto it: color){
        int i = it[2];
        while(true){
            int u = mst.get_top(i);
            if (u == -1) break;
            if (u == mst.get_lck(i)) continue;
            if (mst.same_set(a[u], a[parent[u][0]])) continue;
            mst.join_set(a[u], a[parent[u][0]]);
        }
        mst.push_cc(i, mst.get_lck(i));
        minimize(mi, mst.get_size(i) - 1);
    }
    cout << mi << "\n";
}

int main(void){
    ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);

    clock_t start = clock();

    solve();

    cerr << "Time elapsed: " << clock() - start << " ms\n";
    return 0;
}

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