結果

問題 No.3056 Disconnected Coloring
ユーザー 👑 binap
提出日時 2025-03-14 23:54:57
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 228 ms / 2,000 ms
コード長 3,076 bytes
コンパイル時間 4,596 ms
コンパイル使用メモリ 258,792 KB
実行使用メモリ 15,312 KB
最終ジャッジ日時 2025-03-14 23:55:10
合計ジャッジ時間 11,586 ms
ジャッジサーバーID
（参考情報） 		judge3 / judge4
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 2
other AC * 34
権限があれば一括ダウンロードができます

ソースコード

diff # 

#include<bits/stdc++.h>
#include<atcoder/all>
#define rep(i,n) for(int i=0;i<n;i++)
using namespace std;
using namespace atcoder;
typedef long long ll;
typedef pair<int, int> P;

template <int m> ostream& operator<<(ostream& os, const static_modint<m>& a) {os << a.val(); return os;}
template <int m> ostream& operator<<(ostream& os, const dynamic_modint<m>& a) {os << a.val(); return os;}
template <int m> istream& operator>>(istream& is, static_modint<m>& a) {long long x; is >> x; a = x; return is;}
template <int m> istream& operator>>(istream& is, dynamic_modint<m>& a) {long long x; is >> x; a = x; return is;}
template<typename T> istream& operator>>(istream& is, vector<T>& v){int n = v.size(); assert(n > 0); rep(i, n) is >> v[i]; return is;}
template<typename U, typename T> ostream& operator<<(ostream& os, const pair<U, T>& p){os << p.first << ' ' << p.second; return os;}
template<typename T> ostream& operator<<(ostream& os, const vector<T>& v){int n = v.size(); rep(i, n) os << v[i] << (i == n - 1 ? "\n" : " "); return os;}
template<typename T> ostream& operator<<(ostream& os, const vector<vector<T>>& v){int n = v.size(); rep(i, n) os << v[i] << (i == n - 1 ? "\n" : ""); return os;}
template<typename T> ostream& operator<<(ostream& os, const set<T>& se){for(T x : se) os << x << " "; os << "\n"; return os;}
template<typename T> ostream& operator<<(ostream& os, const unordered_set<T>& se){for(T x : se) os << x << " "; os << "\n"; return os;}
template<typename S, auto op, auto e> ostream& operator<<(ostream& os, const atcoder::segtree<S, op, e>& seg){int n = seg.max_right(0, [](S){return true;}); rep(i, n) os << seg.get(i) << (i == n - 1 ? "\n" : " "); return os;}
template<typename S, auto op, auto e, typename F, auto mapping, auto composition, auto id> ostream& operator<<(ostream& os, const atcoder::lazy_segtree<S, op, e, F, mapping, composition, id>& seg){int n = seg.max_right(0, [](S){return true;}); rep(i, n) os << seg.get(i) << (i == n - 1 ? "\n" : " "); return os;}

template<typename T> void chmin(T& a, T b){a = min(a, b);}
template<typename T> void chmax(T& a, T b){a = max(a, b);}

int main(){
	int n, m;
	cin >> n >> m;
	if(m % 2){
		cout << "-1\n";
		return 0;
	}
	vector<pair<int, int>> G;
	set<int> X, Y, Z;
	rep(i, m){
		int u, v;
		cin >> u >> v;
		u--; v--;
		if(u == 0 and v == n - 1){
			cout << "-1\n";
			return 0;
		}
		G.emplace_back(u, v);
		if(u == 0) X.insert(i);
		else if(v == n - 1) Y.insert(i);
		else Z.insert(i);
	}
	
	string ans;
	rep(i, m) ans += 'R';
	int b = 0;
	atcoder::dsu uf(n);
	
	auto paint = [&](int i){
		auto [u, v] = G[i];
		uf.merge(u, v);
		ans[i] = 'B';
		b++;
	};
	
	if(X.size() + Z.size() <= Y.size()){
		for(auto i : X) paint(i);
		for(auto i : Z) paint(i);
		for(auto i : Y){
			auto [u, v] = G[i];
			if(uf.same(0, u)) continue;
			if(b < m / 2) paint(i);
		}
	}else{
		for(auto i : Y) paint(i);
		for(auto i : Z){
			if(b < m / 2) paint(i);
		}
		for(auto i : X){
			auto [u, v] = G[i];
			if(uf.same(v, n - 1)) continue;
			if(b < m / 2) paint(i);
		}
	}
	cout << ans << "\n";
	return 0;
}
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