Submission #1157060

#	Time	Username	Problem	Language	Result	Execution time	Memory
1157060		SmuggingSpun	One-Way Streets (CEOI17_oneway)	C++20	30 / 100	13 ms	1096 KiB

oneway

#include<bits/stdc++.h>
#define taskname "A"
using namespace std;
const int lim = 1e5 + 5;
int n, m, p, a[lim], b[lim], x[lim], y[lim];
namespace sub1{
	void solve(){
		vector<char>ans(m + 1, 'B');
		vector<int>par(n + 1);
		auto find_set = [&] (int N){
			while(N != par[N]){
				N = par[N] = par[par[N]];
			}	
			return N;
		};
		auto merge = [&] (int u, int v){
			par[find_set(u)] = find_set(v);	
		};
		for(int i = 1; i <= m; i++){
			iota(par.begin(), par.end(), 0);
			for(int j = 1; j <= m; j++){
				if(j != i){
					merge(a[j], b[j]);
				}
			}
			for(int j = 1; j <= p; j++){
				int X = find_set(x[j]), Y = find_set(y[j]);
				if(X != Y){
					if(X == find_set(a[i]) && Y == find_set(b[i])){
						ans[i] = 'R';
						break;
					}
					else if(X == find_set(b[i]) && Y == find_set(a[i])){
						ans[i] = 'L';
						break;
					}
				}
			}
		}
		for(int i = 1; i <= m; i++){
			cout << ans[i];
		}
	}
}
namespace sub23{
	void solve(){
		
	}
}
int main(){
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	if(fopen(taskname".inp", "r")){
		freopen(taskname".inp", "r", stdin);
	}
	cin >> n >> m;
	for(int i = 1; i <= m; i++){
		cin >> a[i] >> b[i];
	}
	cin >> p;
	for(int i = 1; i <= p; i++){
		cin >> x[i] >> y[i];
	}
	if(max(n, m) <= 1000 && p <= 100){
		sub1::solve();
	}
	else{
		sub23::solve();
	}
}

Compilation message (stderr)

oneway.cpp: In function 'int main()':
oneway.cpp:53:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   53 |                 freopen(taskname".inp", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 0 / 30
• Subtask 3: 0 / 40