제출 #1184904

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1184904		tamyte	Joker (BOI20_joker)	C++20	31 / 100	2095 ms	27688 KiB

Joker

#include <bits/stdc++.h>
 
using namespace std;
 
struct DSU {
	vector<int> e;
	DSU(int n) {
		e = vector<int>(n, -1);
	}
	int get(int x) {
		return e[x] < 0 ? x : e[x] = get(e[x]);
	}
	int size(int x) {
		return -e[get(x)];
	}
	bool same(int x, int y) {
		return get(x) == get(y);
	}
	void unite(int x, int y) {
		x = get(x);
		y = get(y);
		if (x == y) return;
		if (e[x] > e[y]) swap(x, y);
		e[x] += e[y];
		e[y] = x;
	}
};
const int N = 2e5;
vector<int> col(N + 1, -1);
vector<bool> vis(N + 1);

void bfs(bool& ok, int x, vector<vector<int>>& adj, int banned) {
	queue<int> q;
	vector<int> used = {x};
	q.push(x);
	vis[x] = true;
	while (q.size()) {
        int v = q.front();
        q.pop();
        for (auto& u : adj[v]) {
        	if (u == banned) continue;
            if (vis[u]) {
            	if (col[v] == col[u]) {
            		ok = true;
            		break;
            	}
            	continue;
            }
            vis[u] = true;
            used.push_back(u);
            col[u] = col[v] ^ 1;
            q.push(u);
        }
    }
    for (auto& u : used) {
    	vis[u] = false;
    }
}

int main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
    int n, m, q;
    cin >> n >> m >> q;
    
    vector<pair<int, int>> a(m);
    for (int i = 0; i < m; ++i) {
        cin >> a[i].first >> a[i].second;
        a[i].first--;
        a[i].second--;
    }
    vector<int> ord(q);
    iota(begin(ord), end(ord), 0);
    vector<array<int, 2>> quer(q);
    for (int i =0 ; i < q; ++i) {
        for (int j = 0; j < 2; ++j) {
            cin >> quer[i][j];
            quer[i][j]--;
        }
    }
    sort(begin(ord), end(ord), [&](const int x, const int y) {
        if (quer[x][0] != quer[x][0]) return quer[x][0] < quer[y][0];
        return quer[x][1] > quer[y][1];
    });
    vector<vector<int>> ordq(200);
    for (int i = 0; i < q; ++i) {
    	ordq[quer[ord[i]][0]].push_back(i);
    }
	vector<bool> res(q);
    vector<vector<int>> adj(n);
	DSU dsu(n);
    for (int _ = 0; _ < 200; ++_) {
	    int k = m - 1;
	    int kl = 0;
	    bool ok = false;
	    set<int> st;
	    for (auto i : ordq[_]) {
	        int j = ord[i];
	        int en = quer[j][1];
	        int enl = quer[j][0];
	        for (int l = kl; l < enl; ++l) {
	        	auto [x, y] = a[l];
	            adj[x].push_back(y);
	            adj[y].push_back(x);
	            if (dsu.same(x, y)) {
	            	if (col[x] == col[y]) {
	            		ok = true;
	            	}
	            } else {
	            	if (dsu.size(x) < dsu.size(y)) swap(x, y);
	            	if (col[x] == -1) col[x] = 0;
	            	col[y] = col[x] ^ 1;
	            	bfs(ok, y, adj, x);
	            	dsu.unite(x, y);
	            }
	            st.insert(x);
	            st.insert(y);
	        }
	        for (int l = k; l > en; --l) {
	            auto [x, y] = a[l];
	            adj[x].push_back(y);
	            adj[y].push_back(x);
	            if (dsu.same(x, y)) {
	            	if (col[x] == col[y]) {
	            		ok = true;
	            	}
	            } else {
	            	if (dsu.size(x) < dsu.size(y)) swap(x, y);
	            	if (col[x] == -1) col[x] = 0;
	            	col[y] = col[x] ^ 1;
	            	bfs(ok, y, adj, x);
	            	dsu.unite(x, y);
	            }
	            st.insert(x);
	            st.insert(y);
	        }
	        kl = enl;
	        k = en;
	        res[j] = ok;
	    }
	    for (auto& u : st) {
	    	col[u] = -1;
	    	dsu.e[u] = -1;
	    	adj[u].clear();
	    }
    }
    for (auto u : res) {
        cout << (u == 1 ? "YES\n" : "NO\n");
    }
}

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