Submission #1127434

#	Time	Username	Problem	Language	Result	Execution time	Memory
1127434		wibulord	Bridges (APIO19_bridges)	C++20	100 / 100	1862 ms	9680 KiB

bridges

#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define pb emplace_back
#define ii pair<int, int>
#define MASK(i) (1LL << (i))
#define BIT(x, i) (((x) >> (i)) & 1)
#define sz(s) (int)((s).size())
#define all(a) a.begin(), a.end()
#define FOR(i, a, b) for (int i = (a), _b = (b); i <= _b; ++i)
#define F0R(i, b) for (int i = 0, _b = (b); i < _b; ++i)
#define FORd(i, a, b) for (int i = (a), _b = (b); i >= _b; --i)
#define F0Rd(i, b) for (int i = (b)-1; i >= 0; i--)
#define debug(...) " [" << #__VA_ARGS__ ": " << (__VA_ARGS__) << "] "
using namespace std;

template<typename T1,typename T2> bool ckmax(T1 &x,const T2 &y){if(x<y){x=y; return 1;} return 0;}
template<typename T1,typename T2> bool ckmin(T1 &x,const T2 &y){if(y<x){x=y; return 1;} return 0;}

const int MOD = (int)1e9 + 7;
const int mod = 998244353;
const int N = 1e5 + 10, S = 1e3 + 1e2 + 10;
const long long INF = (long long)4e18 + 11;

/*
     /\_/\
    (= ._.)
    / >?  \>$
*/

int n, m, q;
struct Egde{
    int u, v, w;
    bool operator < (const Egde &p) const{
        return w > p.w;
    }
}e[N];
int par[N];
stack<ii> st;
int Find(int v){
    while(par[v] > 0) v = par[v];
    return v;
}

bool Union(int u, int v){
    u = Find(u), v = Find(v);
    if(u == v) return false;
    if(par[u] > par[v]) swap(u, v);
    st.push({v, par[v]});
    st.push({u, par[u]});
    par[u] += par[v], par[v] = u;
    return true;
}

void rollback(int tms){
    while(sz(st) > tms){
        auto [v, parV] = st.top(); st.pop();
        par[v] = parV;
        auto [u, parU] = st.top(); st.pop();
        par[u] = parU;
    }
}

struct Query{
    int t, s, w, id;
    void init(){
        id = 0;
        cin >> t >> s >> w;
    }
    bool operator < (const Query &p) const{
        return w > p.w;
    }
}Q[N];
vector<int> T, adj[N];
vector<Egde> E;
vector<Query> QQ;
int res[N];
bool mark[N];

void sol(void){
    cin >> n >> m;
    FOR(i, 1, m){
        int u, v, w; cin >> u >> v >> w;
        e[i] = {u, v, w};
    }
    cin >> q;
    FOR(i, 1, q) Q[i].init();
    FOR(i, 1, n) par[i] = -1;
    for(int B = 1; B <= (q+S-1) / S; B++){
        int l = (B-1)*S + 1, r = min(B*S, q);
        FOR(i, l, r){
            if(Q[i].t == 1){
                int id = Q[i].s;
                mark[id] = true;
                adj[id].push_back(i);
            }
            else QQ.push_back({Q[i].t, Q[i].s, Q[i].w, i});
        }
        FOR(i, 1, m){
            if(mark[i] == true) T.push_back(i);
            else E.push_back(e[i]);
        }
        sort(begin(E), end(E));
        sort(begin(QQ), end(QQ));

        int j = 0;
        for(auto &[t, s, w, id] : QQ){
            while(j < sz(E) && E[j].w >= w){
                Union(E[j].u, E[j].v);
                j++;
            }
            int old = sz(st);
            for(int idx : T){
                int p = upper_bound(all(adj[idx]), id) - adj[idx].begin();
                auto [u, v, c] = e[idx];
                if(p > 0){
                    p--;
                    c = Q[adj[idx][p]].w;
                }
                if(c >= w) Union(u, v);
            }
            res[id] = -par[Find(s)];
            rollback(old);
        }
        FOR(i, l, r) if(Q[i].t == 1){
            int id = Q[i].s;
            mark[id] = false;
            e[id].w = Q[i].w;
            adj[id].clear();
        }
        T.clear(); E.clear(); QQ.clear();
        rollback(0);
    }

    FOR(i, 1, q) if(Q[i].t == 2) cout << res[i] << '\n';
}

signed main(void){
    #define TASK "nhap"
    if(fopen(TASK".inp", "r")){
        freopen(TASK".inp", "r", stdin);
        freopen(TASK".out", "w", stdout);
    }
    ios_base::sync_with_stdio(false); cin.tie(NULL); cout.tie(NULL);
    int t = 1;
//    cin >> t;
    while(t--) sol();
    cerr << "\nTime elapsed: " << 1000 * clock() / CLOCKS_PER_SEC << " ms\n";
}

Compilation message (stderr)

bridges.cpp: In function 'int main()':
bridges.cpp:142:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  142 |         freopen(TASK".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
bridges.cpp:143:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  143 |         freopen(TASK".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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