Submission #1278816

#	Time	Username	Problem	Language	Result	Execution time	Memory
1278816		janson0109	Bridges (APIO19_bridges)	C++20	60 / 100	1959 ms	10388 KiB

bridges

#include <bits/stdc++.h>
#define F first
#define S second
#define lol ios::sync_with_stdio(false);cin.tie(NULL);
typedef int ll;
typedef long double ld;
using namespace std;
const ll M = 998244353;

#define p3 tuple<ll,ll,ll>

ll find(ll x, vector<ll> &p, vector<pair<ll,ll>> &ph, bool his) {
    if(p[x] == x) return x;
    //if(his) ph.push_back({x, p[x]});
    return find(p[x], p, ph, his);
    //return p[x];
}
bool unite(ll x, ll y, vector<ll> &p, vector<ll> &s, vector<pair<ll,ll>> &ph, vector<pair<ll,ll>> &sh, bool his) {
    ll xr = find(x, p, ph, his);
    ll yr = find(y, p, ph, his);
    if(xr == yr) return false;
    if(s[xr] < s[yr]) swap(xr,yr);
    if(his) {
        sh.push_back({xr, s[xr]});
        ph.push_back({yr, p[yr]});
    }
    s[xr]+=s[yr];
    p[yr]=xr;
    return true;
}
void rollback(vector<ll> &p, vector<ll> &s, vector<pair<ll,ll>> &ph, vector<pair<ll,ll>> &sh) {
    while(!ph.empty()) {
        pair<ll,ll> pa = ph.back();
        p[pa.F] = pa.S;
        ph.pop_back();
    }
    while(!sh.empty()) {
        pair<ll,ll> pa = sh.back();
        s[pa.F] = pa.S;
        sh.pop_back();
    }
}

int main() {
	lol
    ll n, m;
    cin >> n >> m;
    vector<p3> e; set<p3, greater<p3>> es;
    for(ll i=0; i<m; i++) {
        ll u, v, d;
        cin >> u >> v >> d;
        u--;v--;
        e.push_back({d, u, v});
        es.insert(e.back());
    }
    ll q; cin >> q;
    vector<p3> qu(q);
    for(ll i=0; i<q; i++) cin >> get<0>(qu[i]) >> get<1>(qu[i]) >> get<2>(qu[i]);
    ll b = sqrtl(q);
    for(ll t=0; t < q; t+=b) {
        ll c = min(b, q-t);
        vector<bool> ch(m,0);
        for(ll i=0; i<c; i++) if(get<0>(qu[t+i]) == 1) ch[get<1>(qu[t+i]) - 1] = 1;
        vector<ll> mod; set<p3> mods;
        for(ll i=0; i<m; i++) if(ch[i]) mod.push_back(i);
        ll k = mod.size(); vector<ll> modm(m, -1);
        vector<ll> nd(k);
        for(ll i=0; i<k; i++) {
            nd[i] = get<0>(e[mod[i]]);
            modm[mod[i]] = i;
            mods.insert(e[mod[i]]);
        }
        vector<vector<ll>> ndm(c);
        for(ll i=0; i<c; i++) {
            if(get<0>(qu[t+i]) == 1) nd[modm[get<1>(qu[t+i]) - 1]] = get<2>(qu[t+i]);
            else ndm[i] = nd;
        }

        vector<p3> qus;
        for(ll i=0; i<c; i++) if(get<0>(qu[t+i]) == 2) qus.push_back({get<2>(qu[t+i]), get<1>(qu[t+i])-1, i});
        sort(qus.begin(), qus.end(), greater<p3>());

        vector<ll> p(n), s(n,1);
        iota(p.begin(), p.end(), 0);
        vector<ll> ans(c, -1);
        auto it = es.begin();
        vector<pair<ll,ll>> ph, sh;
        for(auto & quer : qus) {
            while(it != es.end()) {
                if(mods.find(*it) != mods.end()) it++;
                else if(get<0>(quer) <= get<0>(*it)) {unite(get<1>(*it), get<2>(*it), p, s, ph, sh, 0); it++;}
                else break;
            }
            for(ll j=0; j<k; j++) if(get<0>(quer) <= ndm[get<2>(quer)][j]) unite(get<1>(e[mod[j]]), get<2>(e[mod[j]]), p, s, ph, sh, 1);
            ans[get<2>(quer)] = s[find(get<1>(quer), p, ph, 1)];
            rollback(p, s, ph, sh);
        }
        for(ll i=0; i<c; i++) if(get<0>(qu[t+i]) == 1) {
            auto ite = es.find(e[get<1>(qu[t+i]) - 1]);
            if(ite == es.end()) e[1e9];
            else es.erase(ite);
            get<0>(e[get<1>(qu[t+i]) - 1]) = get<2>(qu[t+i]);
            es.insert(e[get<1>(qu[t+i]) - 1]);
        }
        for(ll i=0; i<c; i++) if(ans[i] != -1) cout << ans[i] << '\n';
    }
    
    
    return 0;
}

Compilation message (stderr)

bridges.cpp: In function 'int main()':
bridges.cpp:100:38: warning: ignoring return value of 'constexpr std::vector<_Tp, _Alloc>::reference std::vector<_Tp, _Alloc>::operator[](size_type) [with _Tp = std::tuple<int, int, int>; _Alloc = std::allocator<std::tuple<int, int, int> >; reference = std::tuple<int, int, int>&; size_type = long unsigned int]', declared with attribute 'nodiscard' [-Wunused-result]
  100 |             if(ite == es.end()) e[1e9];
      |                                      ^
In file included from /usr/include/c++/13/vector:66,
                 from /usr/include/c++/13/functional:64,
                 from /usr/include/x86_64-linux-gnu/c++/13/bits/stdc++.h:53,
                 from bridges.cpp:1:
/usr/include/c++/13/bits/stl_vector.h:1126:7: note: declared here
 1126 |       operator[](size_type __n) _GLIBCXX_NOEXCEPT
      |       ^~~~~~~~

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