Submission #443749

#	Time	Username	Problem	Language	Result	Execution time	Memory
443749		Killer2501	Mergers (JOI19_mergers)	C++14	100 / 100	1338 ms	213000 KiB

mergers

#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define task "slingshot"
#define pll pair<ll, ll>
#define pii pair<pll, ll>
#define fi first
#define se second
#define ull unsigned long long

using namespace std;
const ll mod =  2111992;
const ll N = 5e5+5;
const int base = 300;
ll n, m, t, ans, k, a[N], b[N], c[N], tong,  cnt, q, d[N], P[N][21], h[N], lab[N];
mt19937_64 mt(chrono::steady_clock::now().time_since_epoch().count());

struct point
{
    ll x, y;
}p[N];
vector<ll> dx, dy;
vector<ll> adj[N], kq, gr[N];

string s[N];
ll pw(ll k, ll n)
{
    ll total = 1;
    for(; n; n >>= 1)
    {
        if(n & 1)total = total * k % mod;
        k = k * k % mod;
    }
    return total;
}
ll A(ll u, ll v)
{
    if(u > v)return 0;
    return b[v] * c[v-u] % mod;
}
ll findp(ll u)
{
    return lab[u] < 0 ? u : lab[u] = findp(lab[u]);
}
void hop(ll u, ll v)
{
    u = findp(u);
    v = findp(v);
    if(u == v)return;
    if(lab[u] > lab[v])swap(u, v);
    lab[u] += lab[v];
    lab[v] = u;
}
void add(ll id)
{
    for(; id <= n;id += id & -id)++d[id];
}
ll get(ll id)
{
    ll total = 0;
    for(; id; id -= id & -id)total += d[id];
    return total;
}
ll lwr(ll x)
{
    return lower_bound(kq.begin(), kq.end(), x) - kq.begin() + 1;
}
void dfs(ll u, ll p)
{
    a[u] = ++m;
    for(int i = 1; i <= 20; i ++)P[u][i] = P[P[u][i-1]][i-1];
    for(ll v : adj[u])
    {
        if(v == p)continue;
        h[v] = h[u] + 1;
        P[v][0] = u;
        dfs(v, u);
    }
}
bool cmp(const ll& x, const ll& y)
{
    return a[x] < a[y];
}
ll lca(ll u, ll v)
{
    if(h[u] < h[v])swap(u, v);
    ll log = log2(h[u]);
    for(int i = log; i >= 0; i --)if(h[u] >= h[v] + (1<<i))u = P[u][i];
    if(u == v)return u;
    for(int i = log; i >= 0; i --)
    {
        if(P[u][i] && P[u][i] != P[v][i])
        {
            u = P[u][i];
            v = P[v][i];
        }
    }
    return P[u][0];
}
void cal(ll u, ll p)
{
    for(ll v : adj[u])
    {
        if(v == p)continue;
        cal(v, u);
        c[u] += c[v];
    }
    if(c[u])hop(u, P[u][0]);
}
void sol()
{
    cin >> n >> k;
    for(int i = 1; i < n; i ++)
    {
        ll x, y;
        cin >> x >> y;
        p[i].x = x;
        p[i].y = y;
        adj[x].pb(y);
        adj[y].pb(x);
    }
    for(int i = 1; i <= n; i ++)
    {
        cin >> b[i];
        gr[b[i]].pb(i);
    }
    dfs(1, 0);
    for(int i = 1; i <= k; i ++)
    {
        sort(gr[i].begin(), gr[i].end(), cmp);
        for(int j = 1; j < gr[i].size(); j ++)
        {
            ll x = gr[i][j], y = gr[i][j-1], z = lca(x, y);
            ++c[x];
            ++c[y];
            c[z] -= 2;
        }
    }
    fill_n(lab, n+2, -1);
    cal(1, 0);
    for(int i = 1; i < n; i ++)
    {
        ll u = findp(p[i].x), v = findp(p[i].y);
        if(u != v)
        {
            ++d[u];
            ++d[v];
        }
    }
    for(int i = 1; i <= n; i ++)ans += (d[i] == 1);
    cout << (ans + 1) / 2;
}
int main()
{
    if(fopen(task".in", "r")){
       freopen(task".in", "r", stdin);
       freopen(task".out", "w", stdout);
    }
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int ntest = 1;
    //cin >> ntest;
    while(ntest -- > 0)
    sol();
}

Compilation message (stderr)

mergers.cpp: In function 'void sol()':
mergers.cpp:131:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  131 |         for(int j = 1; j < gr[i].size(); j ++)
      |                        ~~^~~~~~~~~~~~~~
mergers.cpp: In function 'int main()':
mergers.cpp:156:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  156 |        freopen(task".in", "r", stdin);
      |        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
mergers.cpp:157:15: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  157 |        freopen(task".out", "w", stdout);
      |        ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 24 / 24
• Subtask 3: 14 / 14
• Subtask 4: 22 / 22
• Subtask 5: 30 / 30