Submission #1047726

#	Time	Username	Problem	Language	Result	Execution time	Memory
1047726		Lobo	Joker (BOI20_joker)	C++17	100 / 100	158 ms	13248 KiB

Joker

#include<bits/stdc++.h>
using namespace std;
const long long inf = 1e9 + 10;
// #define int long long
#define dbl long double
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()
mt19937_64 rng(chrono::system_clock::now().time_since_epoch().count());
const int maxn = 2e5+10;
// L,R
// (1,L) + (R,M)
// (L+1,R-1)

int n, m, q, isbip = 1, dsz[maxn], ans[maxn];
pair<int,int> ds[maxn], edg[maxn];
vector<pair<pair<int,int>,int>> roll;

pair<int,int> find(int u) {
    if(ds[u].fr == u) return mp(u,0);
    auto aux = find(ds[u].fr);
    return mp(aux.fr,(ds[u].sc^aux.sc));
}
void add(int i) {
    if(i == 0 or i == m+1) {
        roll.pb(mp(mp(0,0),0));
        return;
    }
    int u = edg[i].fr;
    auto auxu = find(u);
    u = auxu.fr;
    int paru = auxu.sc;

    int v = edg[i].sc;
    auto auxv = find(v);
    v = auxv.fr;
    int parv = auxv.sc;
    
    if(u == v && paru == parv) {
        roll.pb(mp(mp(u,v),isbip));
        isbip = 0;
    }
    else if(u != v) {
        if(dsz[u] < dsz[v]) {
            swap(u,v);
            swap(paru,parv);
        }
        roll.pb(mp(mp(u,v),isbip));
        dsz[u]+= dsz[v];
        ds[v].fr = u;
        ds[v].sc = (1^paru^parv);
    }
    else {
        roll.pb(mp(mp(u,v),isbip));
    }
}

void rollback() {
    assert(roll.size());
    if(roll.back().fr.fr == 0) {
        roll.pop_back();
        return;
    }
    int u = roll.back().fr.fr;
    int v = roll.back().fr.sc;
    isbip = roll.back().sc;
    roll.pop_back();
    if(u == v) return;
    ds[u] = mp(u,0);
    ds[v] = mp(v,0);
    dsz[u]-= dsz[v];
}

// pra cada l, eu vejo qual o menor r em que
// cada l, min r -> (1,l) + (r,m) eh bipartido
// comeca sendo 0 m 1 m+1
// (5,7,1,2) pode acontecer (da certo pra tudo)

void sol(int l1, int l2, int r1, int r2) {
    if(l1 > l2) return;
    int l = (l1+l2)/2;
    for(int i = l1+1; i <= l; i++) {
        add(i);
    }
    if(isbip == false) {
        for(int i = l; i <= l2; i++) {
            ans[i] = inf;
        }
        for(int i = l; i >= l1+1; i--) {
            rollback();
        }
        sol(l1,l-1,r1,r2);
        return;
    }
    int r = r2;
    if(isbip == true) {
        while(r-1 >= r1) {
            r--;
            add(r);
            if(isbip == false) {
                rollback();
                r++;
                break;
            }
        }
    }
    ans[l] = r;
    int R = r;
    while(r != r2) {
        r++;
        rollback();
    }
    // r = r2
    add(l+1);
    sol(l+1,l2,R,r2);
    for(int i = l+1; i >= l1+1; i--) {
        rollback();
    }
    while(r != R) {
        r--;
        add(r);
    }
    // r = R
    sol(l1,l-1,r1,R);

    while(r != r2) {
        r++;
        rollback();
    }
    // r = r2
}

void solve() {
    cin >> n >> m >> q;

    for(int i = 1; i <= n; i++) {
        ds[i] = mp(i,0);
        dsz[i] = 1;
    }

    for(int i = 1; i <= m; i++) {
        int u,v;
        cin >> u >> v;
        edg[i] = mp(u,v);
    }
    
    isbip = 1;
    roll.pb(mp(mp(0,0),0));
    roll.pb(mp(mp(0,0),0));
    sol(0,m,1,m+1);
    for(int i = 1; i <= q; i++) {
        int l,r;
        cin >> l >> r;
        if(ans[l-1] <= r+1) {
            cout << "NO" << endl;
        }
        else {
            cout << "YES" << endl;
        }
    }
}

int32_t main() {
    ios::sync_with_stdio(false); cin.tie(0);

    #ifndef ONLINE_JUDGE
    // freopen("in.in", "r", stdin);
    // freopen("out.out", "w", stdout);
    #endif

    int tt = 1;
    // cin >> tt;
    while(tt--) {
        solve();
    }

}

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