Submission #576542

#	Time	Username	Problem	Language	Result	Execution time	Memory
576542		IWannaHaveAGirlfriend	Construction of Highway (JOI18_construction)	C++17	100 / 100	308 ms	17856 KiB

construction

//Make CSP great again
//Vengeance
#include <bits/stdc++.h>
#define TASK "TESTCODE"
#define Log2(x) 31 - __builtin_clz(x)
using namespace std;
const int N = 1e5;
vector<int> adj[N + 1];
int nchain, chain[N + 1], head[N + 1], pos[N + 1], timer, sz[N + 1];
int n, par[N + 1], b[N + 1], c[N + 1];
vector<pair<int, int> > dp[N + 1];
struct FenwickTree
{
    int Tree[N + 1];
    void add(int pos, int val)
    {
        for (; pos <= n; pos |= pos + 1)
        {
            Tree[pos] += val;
        }
    }
    int sum(int pos)
    {
        int ret = 0;
        for (; pos >= 0; pos = (pos & (pos + 1)) - 1)
        {
            ret += Tree[pos];
        }
        return ret;
    }
    int sum(int l, int r)
    {
        return sum(r) - sum(l - 1);
    }
} tree;
void read()
{
    vector<int> id;
    cin >> n;
    for (int i = 1; i <= n; ++ i)
    {
        cin >> c[i];
        id.push_back(i);
    }
    sort(id.begin(), id.end(), [&](const int &x, const int &y)
         {
             return c[x] < c[y];
         });
    int pre = -1, t = 0;
    for (int i : id)
    {
        if (c[i] != pre)
        {
            ++ t;
            pre = c[i];
        }
        c[i] = t;
        //cerr << c[i] << ' ';
    }
    //cerr << '\n';
    for (int i = 1; i < n; ++ i)
    {
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        par[v] = u;
        b[i] = v;
    }
}
void preDFS(int u)
{
    sz[u] = 1;
    for (int v : adj[u])
    {
        preDFS(v);
        sz[u] += sz[v];
    }
}
void HLD(int u)
{
    if (head[nchain] == 0)
    {
        head[nchain] = u;
    }
    chain[u] = nchain;
    pos[u] = ++timer;
    int bigchild = -1;
    for (int v : adj[u])
    {
        if (bigchild == -1 || sz[v] > sz[bigchild])
        {
            bigchild = v;
        }
    }
    if (bigchild != -1)
    {
        HLD(bigchild);
    }
    for (int v : adj[u])
    {
        if (v == bigchild)
        {
            continue;
        }
        ++nchain;
        HLD(v);
    }
}
void solve()
{
    preDFS(1);
    HLD(1);
    dp[0] = {{1, c[1]}};
    for (int i = 1; i < n; ++ i)
    {
        long long res = 0;
        int u = par[b[i]];
        vector<pair<int, int> > total;
        int color = c[b[i]];
        while(u > 0)
        {
            vector<pair<int, int> > f;
            int v = head[chain[u]];
            int pre = pos[head[chain[u]]] - 1;
            //cerr << u << ' ' << pre << ' ' << pos[u] - pos[pre] << '\n';
            while(!dp[chain[u]].empty() && pos[dp[chain[u]].back().first] <= pos[u])
            {
                f.emplace_back(pos[dp[chain[u]].back().first] - pre, dp[chain[u]].back().second);
                pre = pos[dp[chain[u]].back().first];
                dp[chain[u]].pop_back();
            }
            if (!dp[chain[u]].empty())
            {
                f.emplace_back(pos[u] - pre, dp[chain[u]].back().second);
            }
            dp[chain[u]].emplace_back(u, color);
            u = par[v];
            move(f.begin(), f.end(), back_inserter(total));
            while(!f.empty())
            {
                res += 1LL * f.back().first * tree.sum(f.back().second - 1);
                tree.add(f.back().second, f.back().first);
                //cerr << f.back().first << ' ' << f.back().second << '\n';
                f.pop_back();
            }
        }
        dp[chain[b[i]]] = {{b[i], c[b[i]]}};
        for (auto &p : total)
        {
            tree.add(p.second, -p.first);
        }
        cout << res ;
        cout << '\n';
    }
}
int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    if (fopen(TASK".INP", "r"))
    {
        freopen(TASK".INP", "r", stdin);
        //freopen(TASK".OUT", "w", stdout);
    }
    int t = 1;
    bool typetest = false;
    if (typetest)
    {
        cin >> t;
    }
    for (int __ = 1; __ <= t; ++ __)
    {
        //cout << "Case " << __ << ": ";
        read();
        solve();
    }
}

Compilation message (stderr)

construction.cpp: In function 'int main()':
construction.cpp:162:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  162 |         freopen(TASK".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 7 / 7
• Subtask 2: 9 / 9
• Subtask 3: 84 / 84