Submission #1045343

#	Time	Username	Problem	Language	Result	Execution time	Memory
1045343		Lobo	Joker (BOI20_joker)	C++17	14 / 100	2053 ms	26708 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;
const int B = 500;
int n, m, q, col[maxn], colc[2*maxn], ansl[maxn];
vector<int> g[maxn], gc[2*maxn]; 
pair<int,int> edg[maxn];

    int cnt = 0;
bool okcol;
void dfscol(int u) {
    for(auto v : g[u]) {
        if(col[v] == -1) {
            col[v] = (col[u]^1);
            dfscol(v);
        }
        else if(col[v] != (col[u]^1)) {
            okcol = 0;
        }
    }
}
bool okcolc;
void dfscolc(int u) {
    for(auto v : gc[u]) {
        if(colc[v] == -1) {
            colc[v] = (colc[u]^1);
            dfscolc(v);
        }
        else if(colc[v] != (colc[u]^1)) {
            okcolc = 0;
        }
    }
}

void solve() {
    cin >> n >> m >> q;
    for(int i = 1; i <= m; i++) {
        int u,v;
        cin >> u >> v;
        edg[i] = mp(u,v);
    }

    int bLl = 0;
    int bLr = min(m+1,B-1);
    int bRl = 1;
    int bRr = min(m+1,B);
    while(bLl != m+1) {
        for(int i = 1; i <= n; i++) {
            g[i].clear();
            col[i] = -1;
        }
        for(int i = 1; i <= bLl-1; i++) {
            int u = edg[i].fr;
            int v = edg[i].sc;
            g[u].pb(v);
            g[v].pb(u);
        }
        for(int i = bRr+1; i <= m; i++) {
            int u = edg[i].fr;
            int v = edg[i].sc;
            g[u].pb(v);
            g[v].pb(u);
        }
        int cntcol = 0;
        okcol = 1;
        for(int i = 1; i <= n; i++) {
            if(col[i] == -1) {
                colc[cntcol] = -1;
                colc[cntcol+1] = -1;
                col[i] = cntcol;
                cntcol = cntcol+2;
                dfscol(i);
            }
        }
        int L = bLl;
        int R = bRl;

        while(L <= bLr and R <= bRr) {
            vector<int> verts;
            for(int i = bLl; i <= L; i++) {
                if(i == 0 or i == m+1) continue;
                int u = edg[i].fr; verts.pb(col[u]); verts.pb((col[u]^1));
                int v = edg[i].sc; verts.pb(col[v]); verts.pb((col[v]^1));
                gc[col[u]].pb(col[v]);
                gc[col[v]].pb(col[u]);
            }
            for(int i = R; i <= bRr; i++) {
                if(i == 0 or i == m+1) continue;
                int u = edg[i].fr; verts.pb(col[u]); verts.pb((col[u]^1));
                int v = edg[i].sc; verts.pb(col[v]); verts.pb((col[v]^1));
                gc[col[u]].pb(col[v]);
                gc[col[v]].pb(col[u]);
            }
            for(auto i : verts) {
                gc[i].pb((i^1));
            }
            okcolc = 1;
            for(auto i : verts) {
                if(colc[i] == -1) {
                    colc[i] = 0;
                    dfscolc(i);
                }
            }
            if(okcolc == 1 and okcol == 1) {
                ansl[L] = R;
                L++;
            }
            else if(R == m+1) {
                ansl[L] = inf;
                L++;
            }
            else {
                R++;
            }

            for(auto i : verts) {
                colc[i] = -1;
                gc[i].clear();
            }
        }

        bLl = min(m+1,L);
        bLr = (min(m+1,bLl+B-1));
        bRl = min(m+1,R);
        bRr = min(m+1,bRl+B-1);
    }
    // cout << cnt << endl;
    for(int i = 1; i <= q; i++) {
        int l,r;
        cin >> l >> r;
        if(ansl[l-1] <= r+1) {
            cout << "NO" << endl;
        }
        else {
            cout << "YES" << endl;
        }
    }
}

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

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

}

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