Submission #1033874

#	Time	Username	Problem	Language	Result	Execution time	Memory
1033874		goodspeed0208	Joker (BOI20_joker)	C++14	0 / 100	2066 ms	6100 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 == same[x]) return x;
	else return same[x] = find(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;
	}
	if (sz[fa] > sz[fb]) swap(fa, fb); swap(sa, sb);
	f[fa] = fb;
	sz[fb] += sz[fa];
	if ((fa == sa && fb == sb) || (fa != sa && fb != sb)) {
		if (dif[fa] != -1) same[dif[fa]] = same[fb];
		if (dif[fb] != -1) same[fa] = same[dif[fb]];
		else dif[fb] = fa;
	} else {
		same[fa] = same[fb];
		if (dif[fa] != -1 && dif[fb] != -1) same[dif[fa]] = same[dif[fb]];
		else if (dif[fa] != -1) dif[fb] = fa;
	}
	return false;
}

signed main() {
	ios::sync_with_stdio(false);
	cin.tie(0);
	cin >> n >> m >> q;
	f.resize(n);
	sz.resize(n, 1);
	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;
	for (int i = 0 ; i < q ; i++) {
		init();
		bool can = 0;
		cin >> l>> r; l--, r--;
		for (int j = 0 ; j < l && !can ; j++) {
			//cout << e[j].first << " " << e[j].second << "\n";
			can = add(e[j].first, e[j].second);
			//cout << j << " ";
		}
		for (int j = r+1 ; j < m && !can ; j++) {
			can = add(e[j].first, e[j].second);
			//cout << j << " ";
		}
		if (can) cout <<"YES\n";
		else cout << "NO\n";
	}
}

Compilation message (stderr)

Joker.cpp: In function 'bool add(int, int)':
Joker.cpp:35:2: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
   35 |  if (sz[fa] > sz[fb]) swap(fa, fb); swap(sa, sb);
      |  ^~
Joker.cpp:35:37: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
   35 |  if (sz[fa] > sz[fb]) swap(fa, fb); swap(sa, sb);
      |                                     ^~~~

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