Submission #549539

#	Time	Username	Problem	Language	Result	Execution time	Memory
549539		SmolBrain	Factories (JOI14_factories)	C++17	0 / 100	287 ms	56744 KiB

factories

// Om Namah Shivaya
// GM in 108 days

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define endl '\n'
#define pb push_back
#define conts continue
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "YES" << endl
#define no cout << "NO" << endl
#define ff first
#define ss second
#define ceil2(x,y) ((x+y-1) / (y))
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#ifndef ONLINE_JUDGE
#define debug(x) cout << #x <<" = "; print(x); cout << endl
#else
#define debug(x)
#endif

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)

bool iseven(ll n) {if ((n & 1) == 0) return true; return false;}

void print(ll t) {cout << t;}
void print(int t) {cout << t;}
void print(string t) {cout << t;}
void print(char t) {cout << t;}
void print(double t) {cout << t;}
void print(ld t) {cout << t;}

template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(pair <T, V> p) {cout << "{"; print(p.ff); cout << ","; print(p.ss); cout << "}";}
template <class T> void print(vector <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T> void print(set <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T> void print(multiset <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T, class V> void print(map <T, V> v) {cout << "[ "; for (auto i : v) {print(i); cout << " ";} cout << "]";}
template<typename T> void amin(T &a, T b) { a = min(a, b); }
template<typename T> void amax(T &a, T b) { a = max(a, b); }

void usaco(string filename) {
    freopen((filename + ".in").c_str(), "r", stdin);
    freopen((filename + ".out").c_str(), "w", stdout);
}

const int MOD = 1e9 + 7;
const int maxn = 5e5 + 5;
const int inf1 = 1e9 + 5;
const ll inf2 = ll(1e18) + 5;

#include "factories.h"

vector<ll> adj[maxn];
vector<pll> adj2[maxn], adj3[maxn];

struct lca_algo {
    // LCA template (for graphs with 1-based indexing)

    int LOG = 1;
    vector<int> depth;
    vector<vector<int>> up;

    lca_algo() {

    }

    lca_algo(int n) {
        lca_init(n);
    }

    void lca_init(int n) {
        while ((1 << LOG) < n) LOG++;
        up = vector<vector<int>>(n + 1, vector<int>(LOG, 0));
        depth = vector<int>(n + 1);

        lca_dfs(0, -1);
    }

    void lca_dfs(int node, int par) {
        trav(child, adj[node]) {
            if (child == par) conts;

            up[child][0] = node;
            rep1(j, LOG - 1) {
                up[child][j] = up[up[child][j - 1]][j - 1];
            }

            depth[child] = depth[node] + 1;

            lca_dfs(child, node);
        }
    }

    int lift(int u, int k) {
        rep(j, LOG) {
            if (k & (1 << j)) {
                u = up[u][j];
            }
        }

        return u;
    }

    int query(int u, int v) {
        if (depth[u] < depth[v]) swap(u, v);
        int k = depth[u] - depth[v];
        u = lift(u, k);

        if (u == v) return u;

        rev(j, LOG - 1, 0) {
            if (up[u][j] != up[v][j]) {
                u = up[u][j];
                v = up[v][j];
            }
        }

        u = up[u][0];
        return u;
    }
};

template<typename T>
struct segtree {
    // iterative segtree implementation based on this blog:
    // https://codeforces.com/blog/entry/18051
    // thanks to AI.Cash for the educational blog!!!

    /*=======================================================*/

    struct data {
        ll mxdepth, node;
    };

    data neutral = { -1, -1};

    data merge(data &left, data &right) {
        data curr;

        if (left.mxdepth > right.mxdepth) curr = left;
        else curr = right;

        return curr;
    }

    void create(int i, T v) {
        tr[i] = {v.ff, v.ss};
    }

    void modify(int i, T v) {
        tr[i] = {v.ff, v.ss};
    }

    /*=======================================================*/

    int n;
    vector<data> tr;

    segtree() {

    }

    segtree(int siz) {
        init(siz);
    }

    void init(int siz) {
        n = siz;
        tr.assign(2 * n, neutral);
    }

    void build(vector<T> &a, int siz) {
        rep(i, siz) create(i + n, a[i]);
        rev(i, n - 1, 1) tr[i] = merge(tr[i << 1], tr[i << 1 | 1]);
    }

    void pupd(int i, T v) {
        modify(i + n, v);
        for (i += n; i > 1; i >>= 1) tr[i >> 1] = merge(tr[i], tr[i ^ 1]);
    }

    data query(int l, int r) {
        data resl = neutral, resr = neutral;
        for (l += n, r += n; l <= r; l >>= 1, r >>= 1) {
            if (l & 1) resl = merge(resl, tr[l++]);
            if (!(r & 1)) resr = merge(tr[r--], resr);
        }

        return merge(resl, resr);
    }
};

vector<ll> depth(maxn), dis(maxn), tin(maxn), tout(maxn);
ll timer = 0;
lca_algo LCA;
segtree<pll> st;
vector<bool> vis(maxn), type2(maxn);

void dfs1(int node, int par) {
    tin[node] = timer++;

    for (auto [child, w] : adj2[node]) {
        if (child == par) conts;

        depth[child] = depth[node] + 1;
        dis[child] = dis[node] + w;
        dfs1(child, node);
    }

    tout[node] = timer++;
}

void Init(int n, int a[], int b[], int d[]) {
    // editorial approach, but i have used dijkstra instead of dp on trees
    rep(i, n - 1) {
        int u = a[i], v = b[i], w = d[i];
        adj[u].pb(v), adj[v].pb(u);
        adj2[u].pb({v, w}), adj2[v].pb({u, w});
    }

    LCA = lca_algo(n);
    st = segtree<pll>(2 * n + 5);

    dfs1(0, -1);
}

ll getdis(ll u, ll v) {
    ll lca = LCA.query(u, v);
    ll res = dis[u] + dis[v] - 2 * dis[lca];
    return res;
}

ll Query(int n, int a[], int m, int b[]) {
    vector<pll> vals;
    rep(i, n) vals.pb({tin[a[i]], a[i]});
    rep(i, m) vals.pb({tin[b[i]], b[i]});

    sort(all(vals));

    rep(i, n + m - 1) {
        ll u = vals[i].ss, v = vals[i + 1].ss;
        ll lca = LCA.query(u, v);
        vals.pb({tin[lca], lca});
    }

    sort(all(vals));
    auto it = unique(all(vals));
    vals.resize(it - vals.begin());
    ll siz = sz(vals);

    rep(i, siz) {
        ll u = vals[i].ss;
        auto [mxdepth, v] = st.query(tout[u] + 1, timer);

        if (v != -1) {
            ll w = getdis(u, v);
            adj3[u].pb({v, w}), adj3[v].pb({u, w});
        }

        st.pupd(tout[u], {depth[u], u});
    }


    priority_queue< pll, vector<pll>, greater<pll> > pq;
    rep(i, n) pq.push({0, a[i]});

    rep(i, m) type2[b[i]] = 1;

    ll ans = -1;

    while (!pq.empty()) {
        auto [cost, node] = pq.top();
        pq.pop();

        if (vis[node]) conts;
        vis[node] = 1;

        if (type2[node]) {
            ans = cost;
            break;
        }

        for (auto [child, w] : adj3[node]) {
            pq.push({cost + w, child});
        }
    }

    // resetting values
    rep(i, siz) {
        ll u = vals[i].ss;

        st.pupd(tout[u], { -1, -1});

        adj[u].clear();
        vis[u] = 0;
    }

    rep(i, m) type2[b[i]] = 0;

    return ans;
}

Compilation message (stderr)

factories.cpp: In function 'void usaco(std::string)':
factories.cpp:64:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |     freopen((filename + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
factories.cpp:65:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |     freopen((filename + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 15
• Subtask 2: 0 / 18
• Subtask 3: 0 / 67