Submission #648634

#	Time	Username	Problem	Language	Result	Execution time	Memory
648634		mychecksedad	Joker (BOI20_joker)	C++17	25 / 100	198 ms	39140 KiB

Joker

/* Author : Mychecksdead */
#include<bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
using namespace std;
typedef long long int ll;
typedef long double ld;
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define PI 3.1415926535
#define pb push_back
#define setp() cout << setprecision(15)
#define all(x) x.begin(), x.end()
#define oset tree<int, null_type,less_equal<int>, rb_tree_tag,tree_order_statistics_node_update>
#define debug(x) cerr << #x << " is " << x << '\n';
const int N = 1e6+100, M = 2e5+10, F = 2147483646, K = 20;

struct Dsu {
    vector<int> s;
    vector<pair<int, int>> p;
    vector<bool> bp;
    Dsu(int n){
        s.resize(n+1, 1);
        p.resize(n+1);
        bp.resize(n+1);
        for(int i = 0; i <= n; ++i) p[i] = {i, 0}, bp[i] = 1;
    }
    pair<int, int> find_set(int v) {
        if (v != p[v].first) {
            int parity = p[v].second;
            p[v] = find_set(p[v].first);
            p[v].second ^= parity;
        }
        return p[v];
    }
    void merge(int a, int b){
        pair<int, int> pa = find_set(a);
        a = pa.first;
        int x = pa.second;

        pair<int, int> pb = find_set(b);
        b = pb.first;
        int y = pb.second;

        if (a == b) {
            if (x == y)
                bp[a] = 0;
        } else {
            if (s[a] < s[b])
                swap (a, b);
            p[b] = make_pair(a, x^y^1);
            bp[a] = bp[b] & bp[a];
            s[a] += s[b];
        }
    }
};


int n, m, q, l, r;
bool ok;
vector<pair<int, int>> g[N], edges;
bitset<M> vis, pos;
void dfs(int v, int p, bool c){
    vis[v] = 1;
    pos[v] = c;
    for(auto k: g[v]){
        int u = k.first;
        if(l <= k.second && k.second <= r) continue;
        if(u != p){
            if(vis[u])
                ok |= pos[v] == pos[u];
            else
                dfs(u, v, !c);
        }
    }
}
void solve(){
    cin >> n >> m >> q;
    for(int i = 0; i < m; ++i){
        int u, v; cin >> u >> v;
        g[u].pb({v, i + 1});
        g[v].pb({u, i + 1});
        edges.pb({u, v});
    }
    // if(n <= 2000){
    //     for(int i = 0; i < q; ++i){
    //         cin >> l >> r;
    //         vis = 0;
    //         ok = 0;
    //         for(int v = 1; v <= n; ++v) if(!ok && !vis[v]) dfs(v, v, 0);
    //         if(ok) cout << "YES\n";
    //         else cout << "NO\n";
    //     }
    // }
    // else{
        vector<pair<int, int>> queries[205];
        vector<int> qq(q + 1);
        for(int i = 1; i <= q; ++i){
            cin >> l >> r;
            queries[l].pb({r, i});
        }
        for(int i = 1; i <= 200; ++i){
            if(queries[i].empty()) continue;
            Dsu d(n);
            ok = 0;
            for(int j = 1; j < i; ++j){
                d.merge(edges[j - 1].first, edges[j - 1].second);
                ok |= !d.bp[edges[j - 1].first] | !d.bp[edges[j - 1].second];
            }
            sort(all(queries[i]), [&](const pair<int, int> &a, const pair<int, int> &b){
                return a.first > b.first;
            });
            int cur = m;
            for(auto k: queries[i]){
                while(cur > k.first){
                    d.merge(edges[cur - 1].first, edges[cur - 1].second);
                    ok |= !d.bp[d.find_set(edges[cur - 1].first).first] | !d.bp[d.find_set(edges[cur - 1].second).first];
                    cur--;
                }
                qq[k.second] = ok;
            }
        }
        for(int i = 1; i <= q; ++i) cout << (qq[i] ? "YES\n" : "NO\n");
    // }
}



int main(){
    cin.tie(0); ios::sync_with_stdio(0);
    int T = 1, aa;
    // cin >> T;aa=T;
    while(T--){
        // cout << "Case #" << aa-T << ": ";
        solve();
        cout << '\n';
    }
    return 0;
 
}

Compilation message (stderr)

Joker.cpp: In function 'int main()':
Joker.cpp:131:16: warning: unused variable 'aa' [-Wunused-variable]
  131 |     int T = 1, aa;
      |                ^~

• Subtask 1: 0 / 6
• Subtask 2: 0 / 8
• Subtask 3: 25 / 25
• Subtask 4: 0 / 10
• Subtask 5: 0 / 22
• Subtask 6: 0 / 29