Submission #1208015

#	Time	Username	Problem	Language	Result	Execution time	Memory
1208015		onbert	Reconstruction Project (JOI22_reconstruction)	C++20	31 / 100	5119 ms	909308 KiB

reconstruction

#include <bits/stdc++.h>
using namespace std;
#define int long long
struct thing {
    int u, v, w;
    bool operator < (const thing &b) const {
        return w < b.w;
    }
};
const int maxn = 505, maxm = 1e5 + 5, INF = 1e15;
int n;
vector<thing> edge;
vector<int> vals;
int valsz;

int dsu[maxn], sz[maxn];
int rt(int u) {
    if (dsu[u] == u) return u;
    else return dsu[u] = rt(dsu[u]);
}
void merge(int u, int v) {
    if (sz[u] > sz[v]) swap(u, v);
    dsu[u] = v;
    sz[v] += sz[u];
}
vector<thing> pref[maxm], suff[maxm];

signed main() {
    ios::sync_with_stdio(0); cin.tie(0);
    int m;
    cin >> n >> m;
    edge.resize(m);
    for (auto &[u, v, w]:edge) {
        cin >> u >> v >> w;
        vals.push_back(w);
    }
    vals.push_back(-INF); vals.push_back(INF);
    sort(edge.begin(), edge.end());
    sort(vals.begin(), vals.end());
    vals.erase(unique(vals.begin(), vals.end()), vals.end());
    int valsz = vals.size();
    int R = -1;
    for (int i=0;i<valsz;i++) {
        while (R+1 < m && edge[R+1].w <= vals[i]) R++;
        for (int j=1;j<=n;j++) dsu[j] = j, sz[j] = 1;
        for (int j=R;j>=0;j--) {
            auto [u, v, w] = edge[j];
            u = rt(u), v = rt(v);
            if (u != v) {
                merge(u, v);
                pref[i].push_back(edge[j]);
            }
        }
    }
    int L = m;
    for (int i=valsz-1;i>=0;i--) {
        while (L-1 >= 0 && edge[L-1].w >= vals[i]) L--;
        for (int j=1;j<=n;j++) dsu[j] = j, sz[j] = 1;
        for (int j=L;j<m;j++) {
            auto [u, v, w] = edge[j];
            u = rt(u), v = rt(v);
            if (u != v) {
                merge(u, v);
                suff[i].push_back(edge[j]);
            }
        }
    }

    // for (auto [u, v, w]:edge) cout << u << " " << v << " " << w << endl;
    // cout << endl;
    // cout << vals[1] << endl;
    // for (auto [u, v, w]:pref[1]) cout << u << " " << v << " " << w << endl;
    // cout << endl;

    int q;
    cin >> q;
    while (q--) {
        int x;
        cin >> x;
        int pos = lower_bound(vals.begin(), vals.end(), x) - vals.begin();
        int pt1 = 0, pt2 = 0;
        int sz1 = pref[pos-1].size(), sz2 = suff[pos].size();
        int cnt = 0, ans = 0;
        for (int i=1;i<=n;i++) dsu[i] = i, sz[i] = 1;
        while (cnt < n-1) {
            if (pt1 < sz1 && (pt2 >= sz2 || x - pref[pos-1][pt1].w < suff[pos][pt2].w - x)) {
                // cout << "test\n";
                auto [u, v, w] = pref[pos-1][pt1];
                u = rt(u), v = rt(v);
                if (u != v) {
                    cnt++;
                    merge(u, v);
                    ans += x - w;
                }
                pt1++;
            } else {
                auto [u, v, w] = suff[pos][pt2];
                u = rt(u), v = rt(v);
                if (u != v) {
                    cnt++;
                    merge(u, v);
                    ans += w - x;
                }
                pt2++;
            }
            // cout << cnt << " " << pt1 << " " << pt2 << endl;
        }
        cout << ans << "\n";
    }
}

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