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Submission #246935

# Submission time Handle Problem Language Result Execution time Memory
246935 2020-07-10T15:24:04 Z oolimry One-Way Streets (CEOI17_oneway) C++14
60 / 100
 3000 ms 15864 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);
		}
	}
}

vector<ii> tree[100005];
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 = component[edges[i].first];
			int b = component[edges[i].second];
			tree[a].push_back(ii(b,i));
			tree[b].push_back(ii(a,i));
		}
	}
	*/
	
	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){
			//cout << s << " " << t << endl;
			if(depth[s] >= depth[t]){
				//cout << s << " " << labelS << endl;
				if(!pathCompressed[s]) label[s] = labelS;
				pathCompressed[s] = true;
				s = p[s];
			}
			else{
				//cout << t << " " << labelT << endl;
				if(!pathCompressed[t]) label[t] = labelT;
				pathCompressed[t] = true;
				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;
		if(!isBridge[e]) continue;
		
		int a = edges[e].first;
		int b = edges[e].second;
		
		bool swapped = false;
		
		if(depth[a] > depth[b]){
			swap(a, b);
			swapped = true;
		}
		
		//cout << a << " " << b << " " << depth[a] << " " << depth[b] << " " << label[b] << "\n";
		
		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]];
		//if(ans[i] != 0){
		//	cout << ans[i] << " " << edges[i].first << " " << edges[i].second << "\n";
		//}
	}
	
	
	return 0;
}

Compilation message

oneway.cpp: In function 'int main()':
oneway.cpp:114:11: warning: unused variable 'x' [-Wunused-variable]
   for(int x : nodes){
           ^
oneway.cpp:113:7: warning: unused variable 'P' [-Wunused-variable]
   int P = s;
       ^

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5120 KB Output is correct
2 Correct 7 ms 5120 KB Output is correct
3 Correct 8 ms 5120 KB Output is correct
4 Correct 8 ms 5248 KB Output is correct
5 Correct 9 ms 5248 KB Output is correct
6 Correct 8 ms 5120 KB Output is correct
7 Correct 8 ms 5248 KB Output is correct
8 Correct 10 ms 5120 KB Output is correct
9 Correct 8 ms 5120 KB Output is correct
10 Correct 9 ms 5120 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5120 KB Output is correct
2 Correct 7 ms 5120 KB Output is correct
3 Correct 8 ms 5120 KB Output is correct
4 Correct 8 ms 5248 KB Output is correct
5 Correct 9 ms 5248 KB Output is correct
6 Correct 8 ms 5120 KB Output is correct
7 Correct 8 ms 5248 KB Output is correct
8 Correct 10 ms 5120 KB Output is correct
9 Correct 8 ms 5120 KB Output is correct
10 Correct 9 ms 5120 KB Output is correct
11 Correct 52 ms 11512 KB Output is correct
12 Correct 62 ms 12664 KB Output is correct
13 Correct 83 ms 13816 KB Output is correct
14 Correct 106 ms 14840 KB Output is correct
15 Correct 110 ms 14992 KB Output is correct
16 Correct 68 ms 13176 KB Output is correct
17 Correct 83 ms 14968 KB Output is correct
18 Correct 78 ms 13688 KB Output is correct
19 Correct 100 ms 15864 KB Output is correct
20 Correct 67 ms 12536 KB Output is correct
21 Correct 65 ms 12408 KB Output is correct

Subtask #3
0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5120 KB Output is correct
2 Correct 7 ms 5120 KB Output is correct
3 Correct 8 ms 5120 KB Output is correct
4 Correct 8 ms 5248 KB Output is correct
5 Correct 9 ms 5248 KB Output is correct
6 Correct 8 ms 5120 KB Output is correct
7 Correct 8 ms 5248 KB Output is correct
8 Correct 10 ms 5120 KB Output is correct
9 Correct 8 ms 5120 KB Output is correct
10 Correct 9 ms 5120 KB Output is correct
11 Correct 52 ms 11512 KB Output is correct
12 Correct 62 ms 12664 KB Output is correct
13 Correct 83 ms 13816 KB Output is correct
14 Correct 106 ms 14840 KB Output is correct
15 Correct 110 ms 14992 KB Output is correct
16 Correct 68 ms 13176 KB Output is correct
17 Correct 83 ms 14968 KB Output is correct
18 Correct 78 ms 13688 KB Output is correct
19 Correct 100 ms 15864 KB Output is correct
20 Correct 67 ms 12536 KB Output is correct
21 Correct 65 ms 12408 KB Output is correct
22 Execution timed out 3032 ms 14716 KB Time limit exceeded
23 Halted 0 ms 0 KB -