Submission #1033978

#	Time	Username	Problem	Language	Result	Execution time	Memory
1033978		goodspeed0208	Joker (BOI20_joker)	C++14	25 / 100	161 ms	12848 KiB

Joker

#include<bits/stdc++.h>
#define pii pair<int, int>
using namespace std;

int n, m, q;
vector<int>f, sz, same, dif;

void init() {
	for (int i = 0 ; i < n ; i++) {
		f[i] = i;
		same[i] = i;
		dif[i] = -1;
		sz[i] = 1;
	}
}

int find(int x) {
	//if (f[x][j] == -1) return -1;
	if (x == f[x]) return x;
	else return f[x] = find(f[x]);
}

int finds(int x) {
	if (x == -1) return -1;
	if (x == same[x]) return x;
	else return same[x] = finds(same[x]);
}

bool add(int a, int b) {
	int fa = find(a), fb = find(b);
	int sa = finds(a), sb = finds(b);
	//cout << fa << " " << sa << " " << fb << " " << sb << "\n";
	if (fa == fb) {
		if (sa == sb) return true;
		else return false;
	}
	/*if (sz[fa] > sz[fb]) {
		swap(fa, fb); swap(sa, sb);
	}*/
	f[fa] = fb;
	sz[fb] += sz[fa];
	//cout << fa << " " << dif[fa] << " " << finds(dif[fa]) << "\n";
	assert(dif[fa] == finds(dif[fa]));
	assert(dif[fb] == finds(dif[fb]));
	dif[fa] = finds(dif[fa]); dif[fb] = finds(dif[fb]);
	if ((fa == sa && fb == sb) || (fa != sa && fb != sb)) {
		if (dif[fa] != -1) same[dif[fa]] = fb;
		if (dif[fb] != -1) same[fa] = dif[fb];
		else dif[fb] = fa;
	} else {
		same[fa] = fb;
		if (dif[fa] != -1 && dif[fb] != -1) same[dif[fa]] = dif[fb];
		else if (dif[fa] != -1) dif[fb] = dif[fa];
	}
	//for (int i = 0 ; i < n ; i++) cout << find(i) << " "; cout << "\n";
	//for (int i = 0 ; i < n ; i++) cout << finds(i) << " "; cout <<"\n";
	//cout << "\n";
	return false;
}

signed main() {
	//ios::sync_with_stdio(false);
	//cin.tie(0);
	cin >> n >> m >> q;
	f.resize(n);
	sz.resize(n);
	same.resize(n);
	dif.resize(n);
	vector<pii>e;
	int a, b;
	for (int i = 0 ; i < m ; i++) {
		cin >> a >> b; a--, b--;
		e.push_back({a, b});
	}
	int l, r;
	vector<pair<pii, int> >rg(q);
	for (int i = 0 ; i < q ; i++) {
		cin >> rg[i].first.first >> rg[i].first.second;
		rg[i].first.first--; rg[i].first.second--;
		rg[i].second = i;
	}
	sort(rg.begin(), rg.end(), [&](pair<pii, int> x, pair<pii, int> y) {return x.first.second < y.first.second;});
	vector<int>ans(q, 0);
	r = m-1;
	bool can = 0;
	init();
	for (int i = q-1 ; i >= 0 ; i--) {
		//cout <<can << " " << rg[i].first.second << "\n";
		if (can) {
			ans[rg[i].second] = 1;
			continue;
		}
		while (!can && r > rg[i].first.second) {
			//cout << r <<" " <<e[r].first <<" "<< e[r].second << "\n";
			can = add(e[r].first, e[r].second);
			r--;
		}
		if(can) ans[rg[i].second] = 1;
	}
	for (auto i: ans) cout << (i ? "YES" : "NO") << "\n";
}
/*
6 8 5
1 3
1 5
1 6
2 5
2 6
3 4
3 5
5 6
1 8
1 3
1 6
1 2
1 4
*/

Compilation message (stderr)

Joker.cpp: In function 'int main()':
Joker.cpp:75:6: warning: unused variable 'l' [-Wunused-variable]
   75 |  int l, r;
      |      ^

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