Submission #751853

#	Time	Username	Problem	Language	Result	Execution time	Memory
751853		puppy	Reconstruction Project (JOI22_reconstruction)	C++17	3 / 100	5077 ms	786480 KiB

reconstruction

#include <iostream>
#include <vector>
#include <algorithm>
#include <queue>
#define all(v) v.begin(), v.end()
using namespace std;
struct UnionFind
{
    vector<int> par;
    void init(int n){par.resize(n+1); for(int i=1;i<=n;i++) par[i] = i;}
    int fin(int i){return i==par[i]?i:(par[i] = fin(par[i]));}
    void uni(int u, int v){par[fin(u)] = fin(v);}
    bool isuni(int u, int v){return fin(u) == fin(v);}
};
int N, M;
vector<int> inc[2][100005];
struct Edge
{
    int s, e;
    int w;
    bool operator<(const Edge &e)
    {
        return w < e.w;
    }
};
Edge edge[100005];
vector<pair<int, int>> adj[505];
bool visited[505];
pair<int, int> par[505];
signed main()
{
    ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
    cin >> N >> M;
    for (int i = 1; i <= M; i++) {
        int a, b, w; cin >> a >> b >> w;
        edge[i] = {a, b, w};
    }
    sort(edge + 1, edge + M + 1);
    for (int k = 0; k < 2; k++) {
        for (int i = 1; i <= M; i++) {
            fill(visited + 1, visited + N + 1, false);
            for (int t:inc[k][i-1]) inc[k][i].push_back(t);
            int a = edge[i].s, b = edge[i].e;
            visited[a] = true;
            queue<int> q;
            q.push(a);
            while (!q.empty()) {
                int cur = q.front(); q.pop();
                for (pair<int, int> p:adj[cur]) {
                    if (!visited[p.second]) {
                        par[p.second] = make_pair(p.first, cur);
                        visited[p.second] = true; q.push(p.second);
                    }
                }
            }
            if (visited[b]) {
                int mn = i, now = b;
                while (1) {
                    mn = min(mn, par[now].first);
                    now = par[now].second;
                    if (now == a) break;
                }
                inc[k][i].erase(remove(inc[k][i].begin(), inc[k][i].end(), mn), inc[k][i].end());
                inc[k][i].push_back(i);
                int s = edge[mn].s, e = edge[mn].e;
                adj[s].erase(remove(all(adj[s]), make_pair(mn, e)), adj[s].end());
                adj[e].erase(remove(all(adj[e]), make_pair(mn, s)), adj[e].end());
            }
            adj[a].push_back(make_pair(i, b));
            adj[b].push_back(make_pair(i, a));
            inc[k][i].push_back(i);
            inc[k][i].shrink_to_fit();
        }
        for (int i = 1; i <= N; i++) adj[i].clear();
        reverse(edge + 1, edge + M + 1);
    }
    for (int i = 1; i <= M / 2; i++) swap(inc[1][i], inc[1][M+1-i]);
    for (int i = 1; i <= M; i++) {
        for (int &k:inc[1][i]) k = M + 1 - k;
        sort(inc[0][i].begin(), inc[0][i].end(), greater<int>());
        sort(inc[1][i].begin(), inc[1][i].end(), less<int>());
    }
    UnionFind uf;
    int pv = 0;
    int Q; cin >> Q;
    for (int i = 0; i < Q; i++) {
        int X; cin >> X;
        while (pv < M && edge[pv+1].w <= X) pv++;
        int l = 0, r = 0;
        uf.init(N);
        int cnt = N - 1;
        long long ans = 0;
        while (cnt) {
            bool dec = false;
            if (l == (int)inc[0][pv].size()) dec = true;
            else if (r == (int)inc[1][pv+1].size()) dec = false;
            else dec = (X - edge[inc[0][pv][l]].w <= edge[inc[1][pv+1][r]].w - X) ? false : true;
            int use = dec ? inc[1][pv+1][r++] : inc[0][pv][l++];
            if (!uf.isuni(edge[use].s, edge[use].e)) {
                uf.uni(edge[use].s, edge[use].e);
                ans += abs(edge[use].w - X);
                cnt--;
            }
        }
        cout << ans << '\n';
    }
}

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