제출 #1169789

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1169789		InvMOD	Joker (BOI20_joker)	C++20	0 / 100	2094 ms	8252 KiB

Joker

#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define gcd __gcd
#define sz(v) (int) v.size()
#define pb push_back
#define pi pair<int,int>
#define all(v) (v).begin(), (v).end()
#define compact(v) (v).erase(unique(all(v)), (v).end())
#define FOR(i, a, b) for(int i = (a); i <= (b); i++)
#define REV(i, a, b) for(int i = (a); i >= (b); i--)
#define dbg(x) "[" #x " = " << (x) << "]"
///#define int long long

using ll = long long;
using ld = long double;
using ull = unsigned long long;

template<typename T> bool ckmx(T& a, const T& b){if(a < b) return a = b, true; return false;}
template<typename T> bool ckmn(T& a, const T& b){if(a > b) return a = b, true; return false;}

const int N = 2e5+5;
const ll MOD = 1e9+7;
const ll INF = 1e18;


struct DSU{
    vector<int> parity, par;

    stack<pair<int&, int>> st;
    int good = 0;

    void init(int n){
        par.assign(n + 1, -1);
        parity.resize(n + 1);
    }

    int asc(int x){
        return par[x] < 0 ? x : asc(par[x]);
    }

    int get_dist(int x){
        return par[x] < 0 ? parity[x] : parity[x] ^ get_dist(par[x]);
    }

    void join(int u, int v){
        int new_parity = get_dist(u) ^ get_dist(v) ^ 1;

        u = asc(u), v = asc(v);
        if(u == v){
            st.push({good, good});
            good |= new_parity;
        }
        else{
            if(par[u] > par[v]) swap(par[u], par[v]);
            st.push({par[u], par[u]});
            st.push({par[v], par[v]});
            st.push({parity[u], parity[u]});

            par[u] += par[v];
            parity[u] = new_parity;
            par[v] = u;
        }
    }

    bool isGood(){
        return good;
    }

    int snap(){
        return sz(st);
    }

    void rollback(int snipe){
        while(sz(st) > snipe) st.top().fi = st.top().se, st.pop();
    }
};

int n, m, q, ptr, dp[N];

pair<int,int> E[N]; DSU dsu;

void Dnc(int l, int r, int last_pos){
//    cerr << l <<" " << r << "\n";
    if(l > r) return;

    int mid = l+r>>1, snipe = dsu.snap();

    int preptr = ptr;
    for(; ptr < mid; ptr++){
        dsu.join(E[ptr].fi, E[ptr].se);
    }

    int best = -1;
    if(dsu.isGood()){
        best = last_pos;
    }
    else{
        //cout << "Find Good: " << l <<" " << r << "\n";
        for(int pos = last_pos - 1; pos >= mid; pos--){
            dsu.join(E[pos].fi, E[pos].se);
            //cout << "Join: " << E[pos].fi <<" " << E[pos].se << "\n";
            if(dsu.isGood()){
                best = pos;
                break;
            }
        }//cout << "\n";
    }
    dp[mid] = best;

    dsu.rollback(snipe);
    //cout << "DNC JOIN: " << l <<" " << r <<" " << best << " " << ptr << "\n";
    for(int pos = last_pos - 1; pos >= best; pos--){
        dsu.join(E[pos].fi, E[pos].se);
      //  cout << "JOIN: " << E[pos].fi <<" " << E[pos].se << "\n";
    } //cout << "\n";
    ptr = preptr;

    Dnc(l, mid - 1, best);
    Dnc(mid + 1, r, last_pos);
    dsu.rollback(snipe);

    //cout << "DOING JOIN: \n";
    for(; ptr < r + 1; ptr++){
        dsu.join(E[ptr].fi, E[ptr].se);
        //cout << "FIX JOIN: " << E[ptr].fi <<" " << E[ptr].se << "\n";
    } //cout << "\n";
}

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

    FOR(i, 1, m) cin >> E[i].fi >> E[i].se;

    dsu.init(n); ptr = 1;

    FOR(i, 1, m){
        dsu.join(E[i].fi, E[i].se);
    }

    if(!dsu.isGood()){
        FOR(i, 1, q){
            int l,r; cin >> l >> r;
            cout << "NO\n";
        }
        return;
    }
    dsu.rollback(0);

    Dnc(1, m, m + 1);

//    FOR(i, 1, m){
//        cout << dp[i] << " ";
//    } cout << "\n";

    while(q--){
        int l,r; cin >> l >> r;

        cout << (dp[l] > r ? "YES" : "NO") << "\n";
    }
}

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    #define name "InvMOD"
    if(fopen(name".INP", "r")){
        freopen(name".INP","r",stdin);
        freopen(name".OUT","w",stdout);
    }

    int t = 1; //cin >> t;
    while(t--) solve();
    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

Joker.cpp: In function 'int main()':
Joker.cpp:174:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  174 |         freopen(name".INP","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
Joker.cpp:175:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  175 |         freopen(name".OUT","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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