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Submission #246942

# Submission time Handle Problem Language Result Execution time Memory
246942 2020-07-10T15:35:41 Z oolimry One-Way Streets (CEOI17_oneway) C++14
100 / 100
 126 ms 14348 KB 
#include <bits/stdc++.h>
using namespace std;
typedef pair<int,int> ii;

ii edges[100005];
int p[100005];
int label[100005];
int edgeId[100005];

vector<ii> adj[100005];
bool isBridge[100005];
int low[100005];
int depth[100005];
bool pathCompressed[100005];

void tarjan(int u){
	low[u] = depth[u];
	for(ii e : adj[u]){
		int v = e.first, id = e.second;
		if(depth[v] == 0){
			p[v] = u;
			depth[v] = depth[u] + 1;
			tarjan(v);
			if(low[v] > depth[u]) isBridge[id] = true;
			low[u] = min(low[u], low[v]);
			edgeId[v] = id;
		}
		else if(v != p[u]) low[u] = min(low[u], depth[v]);
	}
}

int component[100005];
int cnt = 1;
void compress(int s){
	component[s] = cnt;
	for(ii e : adj[s]){
		int v = e.first, id = e.second;
		if(component[v] == 0 && !isBridge[id]){
			compress(v);
		}
	}
}

int ans[100005];

int main(){
	ios_base::sync_with_stdio(false);
	cin.tie(0);
	int n, m;
	cin >> n >> m;
	
	for(int i = 1;i <= m;i++){
		int a, b; cin >> a >> b;
		edges[i] = ii(a, b);
		adj[a].push_back(ii(b,i));
		adj[b].push_back(ii(a,i));
	}
	
	for(int i = 1;i <= n;i++){
		if(depth[i] != 0) continue;
		depth[i] = 1;
		tarjan(i);
	}
	
	for(int i = 1;i <= n;i++){
		if(component[i] != 0) continue;
		compress(i);
		cnt++;
	}
	
	for(int i = 1;i <= m;i++){
		if(isBridge[i]){
			int a = edges[i].first, b = edges[i].second;
			if(component[a] == component[b]) isBridge[i] = false;
		}
	}
	
	int Q; cin >> Q;	
	while(Q--){
		int s, t; cin >> s >> t;
		int labelS = 1, labelT = 2;
		vector<int> nodes;
		while(s != t){
			if(depth[s] >= depth[t]){
				if(!pathCompressed[s]) label[s] = labelS;
				pathCompressed[s] = true;
				nodes.push_back(s);
				s = p[s];
			}
			else{
				if(!pathCompressed[t]) label[t] = labelT;
				pathCompressed[t] = true;
				nodes.push_back(t);
				t = p[t];
			}
		}
		
		int P = s;
		for(int x : nodes) p[x] = P;
	}
	
	for(int i = 1;i <= n;i++){
		int e = edgeId[i];
		if(e == 0) continue;
		
		int a = edges[e].first;
		int b = edges[e].second;
		
		bool swapped = false;
		
		if(depth[a] > depth[b]){
			swap(a, b);
			swapped = true;
		}
				
		int ANS = label[b];
		if(ANS == 0) continue;
		if(swapped) ANS = 3 - ANS;
		ans[e] = ANS;
	}
	
	string S = "BLR";
	for(int i = 1;i <= m;i++){
		if(!isBridge[i]) ans[i] = 0;
		cout << S[ans[i]];
	}
	
	return 0;
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 2688 KB Output is correct
2 Correct 6 ms 2816 KB Output is correct
3 Correct 8 ms 2816 KB Output is correct
4 Correct 6 ms 2816 KB Output is correct
5 Correct 7 ms 2816 KB Output is correct
6 Correct 6 ms 2816 KB Output is correct
7 Correct 7 ms 2816 KB Output is correct
8 Correct 6 ms 2816 KB Output is correct
9 Correct 6 ms 2816 KB Output is correct
10 Correct 6 ms 2816 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 2688 KB Output is correct
2 Correct 6 ms 2816 KB Output is correct
3 Correct 8 ms 2816 KB Output is correct
4 Correct 6 ms 2816 KB Output is correct
5 Correct 7 ms 2816 KB Output is correct
6 Correct 6 ms 2816 KB Output is correct
7 Correct 7 ms 2816 KB Output is correct
8 Correct 6 ms 2816 KB Output is correct
9 Correct 6 ms 2816 KB Output is correct
10 Correct 6 ms 2816 KB Output is correct
11 Correct 51 ms 8824 KB Output is correct
12 Correct 55 ms 9720 KB Output is correct
13 Correct 60 ms 10928 KB Output is correct
14 Correct 83 ms 11896 KB Output is correct
15 Correct 83 ms 12208 KB Output is correct
16 Correct 68 ms 10256 KB Output is correct
17 Correct 76 ms 12132 KB Output is correct
18 Correct 70 ms 10744 KB Output is correct
19 Correct 62 ms 12920 KB Output is correct
20 Correct 60 ms 9696 KB Output is correct
21 Correct 55 ms 9592 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 2688 KB Output is correct
2 Correct 6 ms 2816 KB Output is correct
3 Correct 8 ms 2816 KB Output is correct
4 Correct 6 ms 2816 KB Output is correct
5 Correct 7 ms 2816 KB Output is correct
6 Correct 6 ms 2816 KB Output is correct
7 Correct 7 ms 2816 KB Output is correct
8 Correct 6 ms 2816 KB Output is correct
9 Correct 6 ms 2816 KB Output is correct
10 Correct 6 ms 2816 KB Output is correct
11 Correct 51 ms 8824 KB Output is correct
12 Correct 55 ms 9720 KB Output is correct
13 Correct 60 ms 10928 KB Output is correct
14 Correct 83 ms 11896 KB Output is correct
15 Correct 83 ms 12208 KB Output is correct
16 Correct 68 ms 10256 KB Output is correct
17 Correct 76 ms 12132 KB Output is correct
18 Correct 70 ms 10744 KB Output is correct
19 Correct 62 ms 12920 KB Output is correct
20 Correct 60 ms 9696 KB Output is correct
21 Correct 55 ms 9592 KB Output is correct
22 Correct 116 ms 12796 KB Output is correct
23 Correct 106 ms 10616 KB Output is correct
24 Correct 126 ms 10676 KB Output is correct
25 Correct 107 ms 14348 KB Output is correct
26 Correct 106 ms 11640 KB Output is correct
27 Correct 99 ms 10616 KB Output is correct
28 Correct 51 ms 6392 KB Output is correct
29 Correct 94 ms 9208 KB Output is correct
30 Correct 89 ms 9340 KB Output is correct
31 Correct 95 ms 9592 KB Output is correct
32 Correct 104 ms 11304 KB Output is correct