oj.uz

Submission #938978

# Submission time Handle Problem Language Result Execution time Memory
938978 2024-03-06T02:28:51 Z vjudge1 One-Way Streets (CEOI17_oneway) C++17
100 / 100
 304 ms 42192 KB 
#include <bits/stdc++.h>
using namespace std;
#define ff first
#define ss second
#define all(a) a.begin(), a.end()
const int N = 2e5;
const int mod = 1e9 + 7;

/*
5 6
1 2
1 2
4 3
2 3
1 3
5 1
2
4 5
1 3
*/
// BBRBBL
signed main(){
	int n, m; cin >> n >> m;
	vector<pair<int, int> > g[n+1];
	vector<pair<int, int> > edge;
	vector<int> dir(m, 0);
	map<pair<int, int>, int> mp;
	for(int i = 0;i < m; i++){
		int a, b; cin >> a >> b;
		edge.push_back({a, b});
		g[a].push_back({b, i});
		g[b].push_back({a, i});
		mp[{a, b}]++;
		mp[{b, a}]++;
	}
	int q; cin >> q;
	vector<pair<int, int> > Q(q);
	vector<pair<int, int>> vert[n+1];
	for(int i = 0;i < q; i++){
		cin >> Q[i].ff >> Q[i].ss;
		vert[Q[i].ff].push_back({Q[i].ss, 0});
		vert[Q[i].ss].push_back({Q[i].ff, 1});
	}
	vector<int>  out(n+1, 0);
	vector<int> tin(n+1), tout(n+1);
	vector<int> ans(m, -1);
	vector<int> used(n+1, 0);
	int timer = 0;
	function<void(int, int)> timers=[&](int v, int p){
		tin[v] = ++timer;
		used[v] = 1;
		for(auto [to, idx] : g[v]){
			if(!used[to] && to != p){
				if(make_pair(v, to) == edge[idx]) dir[idx] = 1;
				timers(to, v);
			}
		}
		tout[v] = timer;
	};
	for(int i = 1;i <= n; i++){
		if(!used[i]){
			timers(i, -1);
		}
	}
	
	pair<int, int> mn[n+1], mx[n+1];
	function<void(int, int)> dfs=[&](int v, int p){
		
		mn[v] = {n+1, -1};
		mx[v] = {-1, -1};
		for(auto [u, t] : vert[v]){
			mn[v] = min(mn[v], make_pair(tin[u], t));
			mx[v] = max(mx[v], make_pair(tout[u], t));
		}
		vector<pair<int, int> > tmp;
		out[v] = tin[v];
		for(auto [to, idx] : g[v]){
			if(to != p){
				if(out[to]){
					out[v] = min(out[v], tin[to]);
				}else{
					dfs(to, v);
					mn[v] = min(mn[v], mn[to]);
					mx[v] = max(mx[v], mx[to]);
					out[v] = min(out[v], out[to]);
					if(out[to] > tin[v]){
						tmp.push_back({to, idx});
					}	
				}
			}
		}
		for(auto [to, idx] : tmp){
			if(mn[to].ff < tin[to]){
				ans[idx] = mn[to].ss;
			}
			if(mx[to].ff > tout[to]){
				ans[idx] = mx[to].ss;
			}
		}
		
	};
	for(int i = 1;i <= n; i++){
		if(!out[i]) dfs(i, i);
	}
	
	for(int i = 0;i < m; i++){
		auto [a, b] = edge[i];
		if(mp[{a, b}] > 1){
			ans[i] = -1;
		}
	}
	for(int i = 0;i < m; i++){
		if(ans[i] == -1){
			cout << 'B';
		}else{
			ans[i]^= dir[i];
			if(ans[i] > 0) cout << 'L';
			else cout << 'R';
		}
	}
	
	
	return 0;
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 2 ms 604 KB Output is correct
4 Correct 2 ms 600 KB Output is correct
5 Correct 1 ms 604 KB Output is correct
6 Correct 1 ms 604 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 2 ms 604 KB Output is correct
9 Correct 1 ms 604 KB Output is correct
10 Correct 1 ms 436 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 2 ms 604 KB Output is correct
4 Correct 2 ms 600 KB Output is correct
5 Correct 1 ms 604 KB Output is correct
6 Correct 1 ms 604 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 2 ms 604 KB Output is correct
9 Correct 1 ms 604 KB Output is correct
10 Correct 1 ms 436 KB Output is correct
11 Correct 190 ms 22520 KB Output is correct
12 Correct 191 ms 24520 KB Output is correct
13 Correct 193 ms 27476 KB Output is correct
14 Correct 256 ms 30408 KB Output is correct
15 Correct 214 ms 30664 KB Output is correct
16 Correct 219 ms 27328 KB Output is correct
17 Correct 213 ms 30728 KB Output is correct
18 Correct 220 ms 27332 KB Output is correct
19 Correct 193 ms 33068 KB Output is correct
20 Correct 175 ms 25028 KB Output is correct
21 Correct 147 ms 23632 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 0 ms 348 KB Output is correct
2 Correct 0 ms 348 KB Output is correct
3 Correct 2 ms 604 KB Output is correct
4 Correct 2 ms 600 KB Output is correct
5 Correct 1 ms 604 KB Output is correct
6 Correct 1 ms 604 KB Output is correct
7 Correct 1 ms 604 KB Output is correct
8 Correct 2 ms 604 KB Output is correct
9 Correct 1 ms 604 KB Output is correct
10 Correct 1 ms 436 KB Output is correct
11 Correct 190 ms 22520 KB Output is correct
12 Correct 191 ms 24520 KB Output is correct
13 Correct 193 ms 27476 KB Output is correct
14 Correct 256 ms 30408 KB Output is correct
15 Correct 214 ms 30664 KB Output is correct
16 Correct 219 ms 27328 KB Output is correct
17 Correct 213 ms 30728 KB Output is correct
18 Correct 220 ms 27332 KB Output is correct
19 Correct 193 ms 33068 KB Output is correct
20 Correct 175 ms 25028 KB Output is correct
21 Correct 147 ms 23632 KB Output is correct
22 Correct 304 ms 36000 KB Output is correct
23 Correct 275 ms 32652 KB Output is correct
24 Correct 281 ms 32708 KB Output is correct
25 Correct 263 ms 42192 KB Output is correct
26 Correct 245 ms 35248 KB Output is correct
27 Correct 294 ms 32984 KB Output is correct
28 Correct 93 ms 8396 KB Output is correct
29 Correct 235 ms 29096 KB Output is correct
30 Correct 239 ms 29664 KB Output is correct
31 Correct 237 ms 30148 KB Output is correct
32 Correct 202 ms 31600 KB Output is correct