Submission #1260381

#	Time	Username	Problem	Language	Result	Execution time	Memory
1260381		khanhdangiuu	Bridges (APIO19_bridges)	C++20	100 / 100	1745 ms	59760 KiB

bridges

//#pragma GCC optimize("O3")
//#pragma GCC optimize("unroll-loops")
#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
template <class T>
using Tree =
    tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
 
#define int long long
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define fi first
#define se second
#define rep(i, a, b) for (int i = a; i <= b; ++i)
#define per(i, b, a) for (int i = b; i >= a; --i)
#define pb push_back
#define eb emplace_back
#define all(v) (v).begin(), (v).end()
#define lsb(x) (x)&(-x)
#define bug(x) cerr << #x << " " << x << endl;
 
void setIO(string name = "") {
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);
    if (!name.empty()) {
        freopen((name + ".in").c_str(), "r", stdin);
        freopen((name + ".out").c_str(), "w", stdout);
    }
}
 
ll fexp(ll a, ll b, ll m) {
    if (b == 0) return 1LL;
    ll p = a;
    ll ans = 1;
    while (b > 0) {
        if (b % 2 != 0) ans = (ans * p) % m;
        p = (p * p) % m;
        b >>= 1;
    }
    return ans;
}
 
const int MAXN = 1e5 + 10;
const int INF = 1e18 + 5;
const int MOD = 1e9+7;
const int B = 1e3;
int u[MAXN],v[MAXN],w[MAXN],n,m,k,q;
int t[MAXN],x[MAXN], y[MAXN], ans[MAXN];
bool mk[MAXN];
vector<int> tj[MAXN];

stack<int> stk;
int sz[MAXN],pr[MAXN];
void reset() {
    iota(pr+1,pr+n+1, 1);
    fill(sz + 1, sz + n + 1, 1);
    fill(mk + 1, mk + m + 1, false);
}

int find(int a) {
    if (a == pr[a]) return a;
    return find(pr[a]);
}

void join(int a, int b) {
    a = find(a); b = find(b);
    if (a==b) return;
    if (sz[a] > sz[b]) swap(a,b);
    stk.push(a);
    sz[b]+=sz[a];
    pr[a] = pr[b];
}

void rollback(int x) {
    while (stk.size() > x) {
        int k = stk.top(); stk.pop();
        sz[pr[k]] -= sz[k];
        pr[k] = k;
    }
}

void solve() {
    cin >> n >> m;
    rep(i,1,m) cin >> u[i] >> v[i] >> w[i];
    cin >> q;
    rep(i,1,q) cin >> t[i] >> x[i] >> y[i];

    for (int l = 1; l <= q; l += B) {
        int r = min(q,l+B-1);
        reset();

        vector<int> ask, upd, unmk;
        rep(i,l,r) {
            if (t[i] == 1) {
                mk[x[i]] = 1;
                upd.pb(i);
            } else {
                ask.pb(i);
            }
        }
        rep(i,1,m) if (!mk[i]) unmk.pb(i);

        rep(i,l,r) {
            if (t[i] == 1) {
                w[x[i]] = y[i];
            } else {
                tj[i-l].clear();
                for (int j : upd)
                {
                    if (w[x[j]] >= y[i]) 
                    {
                        tj[i - l].pb(x[j]);
                    }
                }
            }
        }

        sort(all(ask), [&](int a, int b) { return y[a] > y[b]; });
        sort(all(unmk), [&](int a, int b) { return w[a] > w[b]; });

        int ptr = 0;
        for (int i : ask) {
            while (ptr < unmk.size() && w[unmk[ptr]] >= y[i]) {
                join(u[unmk[ptr]], v[unmk[ptr]]);
                ptr++;
            }

            int tmp = stk.size();
            for (auto i : tj[i-l]) join(u[i], v[i]);
            ans[i] = sz[find(x[i])];
            rollback(tmp);
        }
    }

    rep(i,1,q) if (t[i]==2) cout << ans[i] << '\n';
}

int32_t main() {
    setIO();
    int tt = 1;
    //cin >> tt;
 
    while (tt-- > 0) solve();
    return 0;
}

Compilation message (stderr)

bridges.cpp: In function 'void setIO(std::string)':
bridges.cpp:29:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   29 |         freopen((name + ".in").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
bridges.cpp:30:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   30 |         freopen((name + ".out").c_str(), "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