Submission #1168076

#	Time	Username	Problem	Language	Result	Execution time	Memory
1168076		steveonalex	Joker (BOI20_joker)	C++20	71 / 100	2093 ms	14960 KiB

Joker

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef unsigned long long ull;

#define MASK(i) (1ULL << (i))
#define GETBIT(mask, i) (((mask) >> (i)) & 1)
#define ALL(v) (v).begin(), (v).end()

ll max(ll a, ll b){return (a > b) ? a : b;}
ll min(ll a, ll b){return (a < b) ? a : b;}
ll gcd(ll a, ll b){return __gcd(a, b);}
ll lcm(ll a, ll b){return a / gcd(a, b) * b;}

ll LASTBIT(ll mask){return (mask) & (-mask);}
int pop_cnt(ull mask){return __builtin_popcountll(mask);}
int ctz(ull mask){return __builtin_ctzll(mask);}
int logOf(ull mask){return 63 - __builtin_clzll(mask);}

mt19937_64 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
ll rngesus(ll l, ll r){return l + (ull) rng() % (r - l + 1);}
double rngesus_d(double l, double r){
    double cur = rngesus(0, MASK(60) - 1);
    cur /= MASK(60) - 1;
    return l + cur * (r - l);
}

template <class T1, class T2>
    bool maximize(T1 &a, T2 b){
        if (a < b) {a = b; return true;}
        return false;
    }

template <class T1, class T2>
    bool minimize(T1 &a, T2 b){
        if (a > b) {a = b; return true;}
        return false;
    }

template <class T>
    void printArr(T container, string separator = " ", string finish = "\n", ostream &out = cout){
        for(auto item: container) out << item << separator;
        out << finish;
    }

template <class T>
    void remove_dup(vector<T> &a){
        sort(ALL(a));
        a.resize(unique(ALL(a)) - a.begin());
    }

const int N = 2e5 + 69, BLOCK = 500;

struct DSU{
    int n;
    array<pair<int, int>, N> parent;
    array<int, N> sz;
    int is_valid;

    DSU(int _n){
        n = _n;
    }

    void reset(){
        for(int i = 1; i <= n; ++i) {
            parent[i] = {i, 0};
            sz[i] = 1;
        }
        is_valid = 1;
    }

    pair<int, int> find_set(int u){
        if (u == parent[u].first) return parent[u];
        pair<int, int> v = find_set(parent[u].first);
        v.second ^= parent[u].second;
        return parent[u] = v;
    }

    bool join_set(int x, int y, int w){
        pair<int, int> u = find_set(x), v = find_set(y);
        if (u.first != v.first){
            if (sz[u.first] < sz[v.first]) swap(u, v);
            parent[v.first] = make_pair(u.first, u.second ^ v.second ^ w);
            sz[u.first] += sz[v.first];
            return true;
        }
        if (u.second ^ v.second ^ w) is_valid = 0;
        return false;
    }
};

int n, m, q;
pair<int, int> edge[N];
pair<int, int> queries[N];
vector<int> queries_list[N];
bool ans[N];

DSU mst(N-1);
DSU outer(N-1);

void solve(){
    cin >> n >> m >> q;
    for(int i = 0; i < m; ++i){
        cin >> edge[i].first >> edge[i].second;
    }

    for(int i = 0; i < q; ++i){
        int l, r; cin >> l >> r;
        l--; r--;
        queries[i] = {l, r};
        queries_list[l / BLOCK].push_back(i);
    }

    for(int i = 0; i <= m / BLOCK; ++i) if (queries_list[i].size()){
        sort(ALL(queries_list[i]), [](int x, int y){return queries[x].second < queries[y].second;});

        mst.reset(); outer.reset();
        for(int j = 0; j < i * BLOCK; ++j) mst.join_set(edge[j].first, edge[j].second, 1);

        int r = m-1;
        while(queries_list[i].size()){
            int j = queries_list[i].back(); queries_list[i].pop_back();
            while(r > queries[j].second){
                mst.join_set(edge[r].first, edge[r].second, 1);
                r--;
            }
            if (mst.is_valid == false) continue;
            for(int t = i * BLOCK; t < queries[j].first; ++t){
                pair<int,int> u = mst.find_set(edge[t].first), v = mst.find_set(edge[t].second);
                outer.join_set(u.first, v.first, 1 ^ u.second ^ v.second);
            }

            if (outer.is_valid) ans[j] = true;
            outer.is_valid = true;

            for(int t = i * BLOCK; t < queries[j].first; ++t){
                pair<int,int> u = mst.find_set(edge[t].first), v = mst.find_set(edge[t].second);
                outer.parent[u.first] = make_pair(u.first, 0);
                outer.parent[v.first] = make_pair(v.first, 0);
                outer.sz[u.first] = outer.sz[v.first] = 1;
            }
        }
    }

    for(int i = 0; i< q; ++i) if (ans[i]) cout << "NO\n";
    else cout << "YES\n";
}

int main(void){
    ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);
    clock_t start = clock();

    solve();



    cerr << "Time elapsed: " << clock() - start << " ms!\n";


    return 0;
}

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