Submission #393623

#	Time	Username	Problem	Language	Result	Execution time	Memory
393623		Jarif_Rahman	Bridges (APIO19_bridges)	C++17	30 / 100	3045 ms	10200 KiB

bridges

#include <bits/stdc++.h>
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
#define pb push_back
#define f first
#define sc second
using namespace std;
typedef long long int ll;
typedef string str;
const int N = 5e4, M = 1e5, Q = 1e5, SQ = 223;
struct dsu{
    int n;
    vector<int> sz, p;
    stack<tuple<int, int, int>> st;
    dsu(int nn){
        n = nn;
        sz.resize(n, 1);
        p.resize(n);
        for(int i = 0; i < n; i++) p[i] = i;
    }
    inline int get(int x){
        if(p[x] != x) return get(p[x]);
        return p[x];
    }
    int unite(int a, int b){
        a = get(a), b  = get(b);
        if(a == b) return 0;
        if(sz[b] > sz[a]) swap(a, b);
        st.push({a, b, sz[b]});
        sz[a]+=sz[b];
        sz[b] = 0;
        p[b] = a;
        return 1;
    }
    void rollback(){
        auto [a, b, ss] = st.top(); st.pop();
        sz[a]-=ss;
        sz[b] = ss;
        p[b] = b;
    }
};
int sq;
tuple<ll, int, int> edge[M];
int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n, m; cin >> n >> m;
    for(int i = 0; i < m; i++){
        int a, b; ll w; cin >> a >> b >> w; a--, b--;
        edge[i] = make_tuple(w, a, b);
    }
    int q; cin >> q;
    tuple<ll, int, int> query[Q];
    for(int i = 0; i < q; i++){
        int tt, s; ll w; cin >> tt >> s >> w; s--;
        query[i] = {tt, s, w};
    }
    vector<int> ans;
    dsu ds(N);
    vector<tuple<ll, int, int>> calc;
    bool ucng[M];
    for(int i = 0; i < m; i++) ucng[i] = 1;
    tuple<ll, int, int> edges[M];
    vector<int> cng;
    for(int ql = 0; ql+sq-1 < q; ql+=SQ){
        int qr = min(q-1, ql+SQ-1);
        int cnt = 0;
        for(int j = ql; j <= qr; j++){
            auto [tt, s, w] = query[j];
            if(tt == 1){
                ucng[s] = 0;
            }
            else{
                cnt++;
                calc.pb({w, s, cnt-1});
            }
        }
        int inx = 0;
        for(int i = 0; i < m; i++){
            if(ucng[i]) edges[inx++] = edge[i];
            else cng.pb(i);
        }
        vector<int> anss(cnt);
        vector<vector<pair<int, int>>> upd(cnt);
        cnt = 0;
        for(int j = ql; j <= qr; j++){
            auto [tt, s, w] = query[j];
            if(tt == 1){
                get<0>(edge[s]) = w;
            }
            else{
                for(int x: cng){
                    auto [ww, a, b] = edge[x];
                    if(ww >= w) upd[cnt].pb({a, b});
                }
                cnt++;
            }
        }
        sort(edges, edges+inx);
        sort(calc.rbegin(), calc.rend());
        int bc = inx-1;
        for(auto [w, s, in]: calc){
            while(bc >= 0 && get<0>(edges[bc]) >= w){
                auto [ww, a, b] = edges[bc]; bc--;
                ds.unite(a, b);
            }
            int k = 0;
            for(auto [a, b]: upd[in]) k+=ds.unite(a, b);
            anss[in] = ds.sz[ds.get(s)];
            while(k--) ds.rollback();
        }
        ans.insert(ans.end(), anss.begin(), anss.end());
        calc.clear();
        for(int i = 0; i < m; i++) ucng[i] = 1;
        cng.clear();
        while(!ds.st.empty()) ds.rollback();
    }
    for(int x: ans) cout << x << "\n";
}

Compilation message (stderr)

bridges.cpp:3: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
    3 | #pragma GCC optimization ("O3")
      | 
bridges.cpp:4: warning: ignoring #pragma GCC optimization [-Wunknown-pragmas]
    4 | #pragma GCC optimization ("unroll-loops")
      |

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