Submission #384363

#	Time	Username	Problem	Language	Result	Execution time	Memory
384363		LinusTorvaldsFan	Joker (BOI20_joker)	C++14	71 / 100	2097 ms	20816 KiB

Joker

#pragma GCC optimize("Ofast")


#include <iostream>
#include <string.h>
#include <string>
#include <vector>
#include <algorithm>
#include <map>
#include <assert.h>
#include <cmath>
#include <memory.h>
#include <queue>
#include <bitset>
#include <set>

using namespace std;

#define rep(i, n) for(int i =0;i<(n);i++)
#define per(i, n) for (int i=((int)n-1);i>=0;i--)
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define ff first
#define ss second
#define make_unique(x) { sort(all(x)); x.resize(unique(x.begin(), x.end()) - x.begin()); }
#define sz(x) ((int)x.size())
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define add insert
#define debug(x) { cerr << #x << "= " << x << "\n"; }
typedef long long ll;
typedef vector<int>vi;
typedef vector<ll> vll;
typedef pair<int, int> pii;
typedef vector<pii> vpii;
typedef pair<ll, ll> pll;
typedef vector<string> vs;
const int N = 200100;
int dsu[2 * N];
int sz[2 * N];

bool is_bipar = true;

vector<tuple<int, int, int, int>> ba;
vector<bool> bipar;


inline int find(int x) {
	while (x != dsu[x]) x = dsu[x];
	return x;
}

inline void unite(int a, int b) {
	
	a = find(a);
	b = find(b);

	if (sz[a] < sz[b]) swap(a, b);
	
	if (a == b) return;

	
	bipar.pb(is_bipar);
	ba.eb(a, sz[a], b, dsu[b]);

	dsu[b] = a;
	sz[a] += sz[b];

}

bool same(int a, int b) {
	return find(a) == find(b);
}

void merge(int a, int b) {

	unite(a, b + N);
	unite(b, a + N);

	if (same(a, a + N) || same(b, b + N)) {
		is_bipar = false;
	}
}

void back() {
	int a, b, c, d;
	tie(a, b, c, d) = ba.back();
	sz[a] = b;
	dsu[c] = d;
	is_bipar = bipar.back();
	ba.pop_back();
	bipar.pop_back();
}

void init() {
	rep(i, 2 * N) {
		dsu[i] = i;
		sz[i] = 1;
	}
}

bool ans[N];

struct Q {
	int l, r, i;
};

bool operator<(Q a, Q b) {
	return a.r > b.r;
}

vector<Q> qu[N];

int main() {
	bipar.reserve(2 * N);
	ba.reserve(2 * N);
	ios_base::sync_with_stdio(0);
	cin.tie(0);
	int n, m, q;
	cin >> n >> m >> q;
	vpii edges;
	rep(i, m) {
		int u, v;
		cin >> u >> v;
		edges.eb(u, v);
	}
	const int K = 2200;

	rep(i, q) {
		int l, r;
		cin >> l >> r;
		l--; r--;
		qu[l / K].pb({ l, r, i });
	}
	init();
	rep(bl, N) {
		int bl_l = bl * K;
		int bl_r = min((bl + 1) * K - 1, m - 1);
		if (qu[bl].size()) {
			sort(all(qu[bl]));
			int pr = m - 1;
			int was_on_start = ba.size();
			rep(j, sz(qu[bl])) {
				while (pr > qu[bl][j].r) {
					int v1 = edges[pr].ff;
					int v2 = edges[pr].ss;
					pr--;
					merge(v1, v2);
				}
				int was = ba.size();
				for (int i = qu[bl][j].l - 1; i >= bl_l; i--) {
					int v1 = edges[i].ff;
					int v2 = edges[i].ss;
					merge(v1, v2);
				}
				ans[qu[bl][j].i] = is_bipar;
				while (ba.size() != was) {
					back();
				}
			}

			while (ba.size() != was_on_start) {
				back();
			}
		}
		for (int i = bl_l; i <= bl_r; i++) {
			int v1 = edges[i].ff;
			int v2 = edges[i].ss;
			merge(v1, v2);
		}
	}

	rep(i, q) {
		if (ans[i]) cout << "NO\n";
		else cout << "YES\n";
	}

	return 0;
}

Compilation message (stderr)

Joker.cpp: In function 'int main()':
Joker.cpp:158:22: warning: comparison of integer expressions of different signedness: 'std::vector<std::tuple<int, int, int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  158 |     while (ba.size() != was) {
      |            ~~~~~~~~~~^~~~~~
Joker.cpp:163:21: warning: comparison of integer expressions of different signedness: 'std::vector<std::tuple<int, int, int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
  163 |    while (ba.size() != was_on_start) {
      |           ~~~~~~~~~~^~~~~~~~~~~~~~~

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