Submission #368001

#	Time	Username	Problem	Language	Result	Execution time	Memory
368001		Jarif_Rahman	Bridges (APIO19_bridges)	C++17	59 / 100	3083 ms	11368 KiB

bridges

#include <bits/stdc++.h>
#define pb push_back
#define f first
#define sc second
using namespace std;
typedef long long int ll;
typedef string str;
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;
    }
    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;
bool comp(tuple<ll, int, int, vector<pair<int, int>>> a, tuple<ll, int, int, vector<pair<int, int>>> b){return get<0>(a) > get<0>(b);}
int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    int n, m; cin >> n >> m;
    vector<tuple<ll, int, int>> edge;
    for(int i = 0; i < m; i++){
        int a, b; ll w; cin >> a >> b >> w; a--, b--;
        edge.pb({w, a, b});
    }
    int q; cin >> q;
    sq = sqrt(q+0.0);
    vector<vector<tuple<ll, int, int, int>>> query;
    query.pb({});
    int inx = 0;
    for(int i = 0; i < q; i++){
        int tt, s; ll w; cin >> tt >> s >> w; s--;
        int in = -1;
        if(tt == 2) in = inx++;
        if(query.back().size() >= sq) query.pb({});
        query.back().pb({tt, s, w, in});
    }
    vector<int> ans(inx);
    for(auto qq: query){
        dsu ds(n);
        vector<tuple<ll, int, int, vector<pair<int, int>>>> calc;
        vector<bool> ucng(m, 1);
        vector<tuple<ll, int, int>> edges;
        vector<tuple<int, ll, int, int>> cng;
        for(auto [tt, s, w, in]: qq) if(tt == 1) ucng[s] = 0;
        for(int i = 0; i < m; i++){
            if(ucng[i]) edges.pb(edge[i]);
            else cng.pb({i, get<0>(edge[i]), get<1>(edge[i]), get<2>(edge[i])});
        }
		map<int, int> mp;
		for(int i = 0; i < cng.size(); i++) mp[get<0>(cng[i])] = i;
        for(auto [tt, s, w, in]: qq){
            if(tt == 1){
                auto &[ss, ww, a, b] = cng[mp[s]];
				ww = w;
            }
            else{
                vector<pair<int, int>> upd;
                for(auto [inn, ww, a, b]: cng) if(ww >= w) upd.pb({a, b});
                calc.pb({w, s, in, upd});
            }
        }
        sort(edges.begin(), edges.end());
        sort(calc.begin(), calc.end(), comp);
        for(auto [w, s, in, upd]: calc){
            while(!edges.empty() && get<0>(edges.back()) >= w){
                auto [ww, a, b] = edges.back(); edges.pop_back();
                ds.unite(a, b);
            }
            int k = 0;
            for(auto [a, b]: upd) k+=ds.unite(a, b);
            ans[in] = ds.sz[ds.get(s)];
            while(k--) ds.rollback();
        }
        for(auto [tt, s, w, in]: qq) if(tt == 1){
            get<0>(edge[s]) = w;
        }
    }
    for(int x: ans) cout << x << "\n";
}

Compilation message (stderr)

bridges.cpp: In function 'int main()':
bridges.cpp:59:32: warning: comparison of integer expressions of different signedness: 'std::vector<std::tuple<long long int, int, int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   59 |         if(query.back().size() >= sq) query.pb({});
      |            ~~~~~~~~~~~~~~~~~~~~^~~~~
bridges.cpp:75:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::tuple<int, long long int, int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   75 |   for(int i = 0; i < cng.size(); i++) mp[get<0>(cng[i])] = i;
      |                  ~~^~~~~~~~~~~~

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