Submission #963949

#	Time	Username	Problem	Language	Result	Execution time	Memory
963949		GrindMachine	Reconstruction Project (JOI22_reconstruction)	C++17	42 / 100	5079 ms	790448 KiB

reconstruction

#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<typename 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 pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#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 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)

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);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*

refs:
some solutions

*/

const int MOD = 1e9 + 7;
const int N = 500 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;

struct DSU {
    vector<int> par, rankk, siz;

    DSU() {

    }

    DSU(int n) {
        init(n);
    }

    void init(int n) {
        par = vector<int>(n + 1);
        rankk = vector<int>(n + 1);
        siz = vector<int>(n + 1);
        rep(i, n + 1) create(i);
    }

    void create(int u) {
        par[u] = u;
        rankk[u] = 0;
        siz[u] = 1;
    }

    int find(int u) {
        if (u == par[u]) return u;
        else return par[u] = find(par[u]);
    }

    bool same(int u, int v) {
        return find(u) == find(v);
    }

    void merge(int u, int v) {
        u = find(u), v = find(v);
        if (u == v) return;

        if (rankk[u] == rankk[v]) rankk[u]++;
        if (rankk[u] < rankk[v]) swap(u, v);

        par[v] = u;
        siz[u] += siz[v];
    }
};

vector<pll> adj[N];
vector<ll> active;
ll mn_on_path;

void dfs1(ll u, ll p, ll des, ll mn){
    if(u == des){
        mn_on_path = mn;
    }

    for(auto [v,id] : adj[u]){
        if(v == p) conts;
        dfs1(v,u,des,min(mn,id));
    }
} 

void solve(int test_case)
{
    ll n,m; cin >> n >> m;
    vector<array<ll,3>> edges(m+5);
    rep1(i,m){
        ll u,v,w; cin >> u >> v >> w;
        edges[i] = {w,u,v};
    }

    sort(edges.begin()+1,edges.begin()+m+1);

    vector<ll> edges_front[m+5], edges_back[m+5];

    rep1(i,m){
        mn_on_path = inf2;
        auto [w,u,v] = edges[i];
        dfs1(u,-1,v,inf2);
        if(mn_on_path != inf2){
            auto [w,x,y] = edges[mn_on_path];
            active.erase(find(all(active),mn_on_path));
            pll px = {x,mn_on_path}, py = {y,mn_on_path};
            adj[x].erase(find(all(adj[x]),py));
            adj[y].erase(find(all(adj[y]),px));
        }

        active.pb(i);
        adj[u].pb({v,i}), adj[v].pb({u,i});

        edges_front[i] = active;
    }

    rep1(i,n){
        adj[i].clear();
    }

    active.clear();

    rev(i,m,1){
        mn_on_path = inf2;
        auto [w,u,v] = edges[i];
        dfs1(u,-1,v,inf2);
        if(mn_on_path != inf2){
            mn_on_path = -mn_on_path;
            auto [w,x,y] = edges[mn_on_path];
            active.erase(find(all(active),mn_on_path));
            pll px = {x,-mn_on_path}, py = {y,-mn_on_path};
            adj[x].erase(find(all(adj[x]),py));
            adj[y].erase(find(all(adj[y]),px));
        }

        active.pb(i);
        adj[u].pb({v,-i}), adj[v].pb({u,-i});

        edges_back[i] = active;
    }

    ll q; cin >> q;

    while(q--){
        ll x; cin >> x;
        array<ll,3> ar = {x,-1,-1};
        ll pos = lower_bound(edges.begin()+1,edges.begin()+m+1,ar)-edges.begin();
        vector<array<ll,3>> curr_edges;
        trav(id,edges_front[pos-1]){
            auto [w,u,v] = edges[id];
            w = abs(w-x);
            curr_edges.pb({w,u,v});
        }
        trav(id,edges_back[pos]){
            auto [w,u,v] = edges[id];
            w = abs(w-x);
            curr_edges.pb({w,u,v});
        }

        sort(all(curr_edges));

        DSU dsu(n+5);
        ll ans = 0;

        for(auto [w,u,v] : curr_edges){
            if(dsu.same(u,v)) conts;
            dsu.merge(u,v);
            ans += w;
        }

        cout << ans << endl;
    }
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;

    rep1(i, t) {
        solve(i);
    }

    return 0;
}

• Subtask 1: 3 / 3
• Subtask 2: 4 / 4
• Subtask 3: 0 / 7
• Subtask 4: 0 / 28
• Subtask 5: 35 / 35
• Subtask 6: 0 / 23