Submission #129758

#	Time	Username	Problem	Language	Result	Execution time	Memory
129758		pr3pony	Bridges (APIO19_bridges)	C++14	73 / 100	3035 ms	10088 KiB

bridges

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 51212, M = 121212, Q = 121212;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
#define F first
#define S second
pii e[M];
int d[M], la[M], ans[Q], dsu[N], vis[N], qu[N], vct;
vector<int> g[N];
int find(int u) {return dsu[u] < 0 ? u : dsu[u] = find(dsu[u]);}
void meld(int u,int v)
{
    u = find(u), v = find(v);
    if (u == v)
        return;
    if (dsu[v] < dsu[u])
        swap(u,v);
    dsu[u] += dsu[v];
    dsu[v] = u;
}
set<pii,greater<pii>> se;
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    int n,m,q;
    cin >> n >> m;
    for (int i = 1; i <= m; ++i) {
        cin >> e[i].F >> e[i].S >> d[i];
        se.emplace(d[i],i);
    }
    const int BS = sqrt(n+m)+1;
    vector<tuple<int,int,int>> qry; // w, vertex id, time
    vector<tuple<int,int,int,int>> ce; // edge id, time l, time r, w
    vector<int> cv;
    cin >> q;
    for (int i = 1, lt = 0; i <= q; ++i) {
        int a,b,c;
        cin >> a >> b >> c;
        if (a == 1) {
            ce.emplace_back(b,la[b],i-1,d[b]);
            la[b] = i;
            se.erase({d[b],b});
            d[b] = c;
            se.emplace(d[b],b);
        } else {
            qry.emplace_back(c,b,i);
        }
        if (qry.size() * ce.size() * 4 >=  BS * BS || i == q) {
            for (int j = 1; j <= m; ++j)
                if (la[j] > lt) 
                    ce.emplace_back(j,la[j],i,d[j]);
            sort(begin(ce),end(ce),[](const tuple<int,int,int,int>& x,const tuple<int,int,int,int>& y){return get<3>(x)>get<3>(y);});
            auto it = begin(se);
            sort(begin(qry),end(qry),greater<decltype(qry[0])>());
            fill_n(dsu,n+1,-1);
            for (const auto & tu : qry) {
                int w,vi,t;
                tie(w,vi,t) = tu;
                for (;it != end(se) && it->F >= w; ++it) {
                    int ei = it->S;
                    if (la[ei] <= lt) {
                        meld(e[ei].F,e[ei].S);
                    }
                }
                cv.clear();
                for (const auto & eu : ce) {
                    int ei,tl,tr,ew;
                    tie(ei,tl,tr,ew) = eu;
                    if (ew < w)
                        break;
                    int u = find(e[ei].F), v = find(e[ei].S);
                    if (tl <= t && t <= tr && u != v) {
                        g[u].emplace_back(v);
                        g[v].emplace_back(u);
                        cv.emplace_back(u);
                        cv.emplace_back(v);
                    }
                }
                vi = find(vi);
                int ta = dsu[vi], ql=0, qr=0;
                qu[qr++] = (vi);
                vis[vi] = ++vct;
                while (qr - ql) {
                    int u = qu[ql++];
                    for (int v : g[u])
                        if (vis[v] != vct) {
                            vis[v] = vct;
                            qu[qr++] = v;
                            ta += dsu[v];
                        }
                }
                ans[t] = -ta;
                for (int u : cv)
                    g[u].clear();
            }
            qry.clear();
            ce.clear();
            lt = i;
        }
    }
    for (int i = 1; i <= q; ++i)
        if (ans[i])
            cout << ans[i] << '\n';
}

• Subtask 1: 13 / 13
• Subtask 2: 16 / 16
• Subtask 3: 17 / 17
• Subtask 4: 14 / 14
• Subtask 5: 13 / 13
• Subtask 6: 0 / 27