Submission #1298866

#TimeUsernameProblemLanguageResultExecution timeMemory
1298866floJoker (BOI20_joker)C++20
39 / 100
2096 ms76468 KiB
#include <bits/stdc++.h>
#define task "testing"
#define ll long long
#define multitest 0
using namespace std;

struct Edge {
	int u, v;
};

struct Queries {
	int l, r;
};

const int N = 2e5;

int n, m, q;

Edge E[2*N+5];

Queries Q[N+5];

bitset<N+5> res;

namespace sub12 {
	const int sN = 2e3;
	
	int dsu[2*sN+5];
	
	void reset() {
		fill(dsu+1, dsu+2*n+1, -1);
	}
	
	int root(int v) {
		return dsu[v] < 0 ? v : dsu[v] = root(dsu[v]);
	}
	
	void unite(int u, int v) {
		if ((u = root(u)) == (v = root(v))) return;
		
		if (dsu[u] > dsu[v]) swap(u, v);
		
		dsu[u] += dsu[v], dsu[v] = u;
	}
	
	bool connect(int u, int v) {
		return root(u) == root(v);
	}
	
	bool check() {
		return max({n, m, q}) <= sN;
	}
	
	bool qry(int l, int r) {
		reset();
		
		for (int x = l; x <= r; x++) {
			unite(E[x].u, E[x].v+n);
			unite(E[x].u+n, E[x].v);
		}
		
		for (int x = 1; x <= n; x++) {
			if (connect(x, x+n)) return 1;
		}
		
		return 0;
	}
	
	void solve() {
		for (int x = 1; x <= q; x++) {
			if (qry(Q[x].r+1, Q[x].l+m-1)) res.set(x);
		}
	}
}

namespace sub34 {
	const int L = 200;
	
	set<int> st[2*N+5];
	
	int dsu[2*N+5], rt[L+5], mxL;
	
	bool check() {
		mxL = 0;
		
		for (int x = 1; x <= q; x++) {
			mxL = max(mxL, Q[x].l);
		}
		
		return mxL <= L;
	}
	
	int flip(int v) {
		return v+(v <= n ? n : -n);
	}
	
	void reset() {
		for (int x = 2*n; x >= 1; x--) {
			dsu[x] = -1, st[x] = {x};
		}
	}
	
	int root(int v) {
		return dsu[v] < 0 ? v : dsu[v] = root(dsu[v]);
	}
	
	bool unite(int u, int v) {
		if ((u = root(u)) == (v = root(v))) return 0;
		
		if (dsu[u] > dsu[v]) swap(u, v);
		
		dsu[u] += dsu[v], dsu[v] = u;
		
		for (auto x : st[v]) {
			if (st[u].find(flip(x)) != st[u].end()) return 1;
			
			st[u].insert(x);
		}
		
		return 0;
	}
	
	void calc(int l) {	
		reset();
		
		bool ex = 0;
		
		for (int x = 1; x < l && !ex; x++) {
			ex |= unite(E[x].u, E[x].v+n);
			ex |= unite(E[x].u+n, E[x].v);
		}
		
		if (ex) rt[l] = m+1;
		
		for (int r = m; r > l && !ex; r--) {
			ex |= unite(E[r].u, E[r].v+n);
			ex |= unite(E[r].u+n, E[r].v);
			
			if (ex) rt[l] = r;
		}
	}
	
	void solve() {
		for (int x = min(m, mxL); x >= 1; x--) calc(x);
		
		for (int x = 1; x <= q; x++) {
			if (Q[x].r < rt[Q[x].l]) res.set(x);
		}
	}
}

void flo(int ID) {
	cin >> n >> m >> q;
	
	for (int x = 1; x <= m; x++) {
		cin >> E[x].u >> E[x].v;
		
		E[x+m] = E[x];
	}
	
	for (int x = 1; x <= q; x++) {
		cin >> Q[x].l >> Q[x].r;
	}
	
	if (sub12::check()) sub12::solve();
	else if (sub34::check()) sub34::solve();
	
	for (int x = 1; x <= q; x++) {
		cout << (res.test(x) ? "YES\n" : "NO\n");
	}
}

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

	if (fopen(task".inp", "r")) {
		freopen(task".inp", "r", stdin);
		freopen(task".out", "w", stdout);
	}

	int TCS = 1, ID = 1;

	if (multitest) {
		cin >> TCS;
	}

	while (TCS--) flo(ID++);

	return 0;
}

Compilation message (stderr)

Joker.cpp: In function 'int main()':
Joker.cpp:178:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  178 |                 freopen(task".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
Joker.cpp:179:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  179 |                 freopen(task".out", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
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