/* Author : Mychecksdead */
#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define PI 3.1415926535
#define pb push_back
#define all(x) x.begin(), x.end()
const int N = 1e5+100, M = 1e5+10, K = 20;
int n, m, p, tin[N], tout[N], up[N][K], par[N][2], lo[N], timer = 0, ti[N];
vector<pair<int, int>> g[N], f[N];
vector<bool> vis, bridge;
string s;
void st(int v){
vis[v] = 1;
for(auto U: g[v]){
int u = U.first, idx = U.second;
if(!vis[u]){
f[v].pb({u, idx});
f[u].pb({v, idx^1});
par[u][0] = v;
par[u][1] = idx;
st(u);
}
}
}
void pre(int v, int p){
tin[v] = timer++;
for(auto U: f[v]){
int u = U.first;
if(u != p){
up[u][0] = v, pre(u, v);
}
}
tout[v] = timer++;
}
bool is_ancestor(int u, int v){
return tin[u] <= tin[v] && tout[v] <= tout[u];
}
int _lca(int u, int v){
if(is_ancestor(u, v)) return u;
if(is_ancestor(v, u)) return v;
for(int j = K - 1; j >= 0 ;--j){
if(!is_ancestor(up[u][j], v)) u = up[u][j];
}
return up[u][0];
}
void bf(int v, int pp){
ti[v] = lo[v] = timer++;
vis[v] = 1;
for(auto U: g[v]){
int u = U.first, idx = U.second;
if(idx/2 == pp/2) continue;
if(vis[u]){
lo[v] = min(lo[v], ti[u]);
}else{
bf(u, idx);
lo[v] = min(lo[v], lo[u]);
if(lo[u] > ti[v]){
bridge[idx>>1] = 1;
}
}
}
}
void solve(){
cin >> n >> m;
for(int i = 0 ; i < m; ++i){
int u, v; cin >> u >> v;
g[u].pb({v, i*2});
g[v].pb({u, i*2+1});
s += 'B';
}
vis.resize(n + 1, 0);
st(1);
pre(1, 0);
up[1][0] = 1;
for(int j = 1; j < K; ++j) for(int i = 1; i <= n; ++i) up[i][j] = up[up[i][j - 1]][j - 1];
vis.clear();
vis.resize(n + 1, 0);
bridge.resize(m, 0);
timer = 0;
bf(1, MOD);
vis.clear();
vis.resize(m, 0);
cin >> p;
for(int i = 0; i < p; ++i){
int u, v; cin >> u >> v;
int lca = _lca(u, v);
while(v != lca){
if(vis[par[v][1]>>1]) break;
vis[par[v][1]>>1] = 1;
if(bridge[par[v][1]>>1])
s[par[v][1]>>1] = ((par[v][1] & 1) ^ 1) ? 'R' : 'L';
v = par[v][0];
}
while(u != lca){
if(vis[par[u][1]>>1]) break;
vis[par[u][1]>>1] = 1;
if(bridge[par[u][1]>>1])
s[par[u][1]>>1] = (par[u][1] & 1) ? 'R' : 'L';
u = par[u][0];
}
}
cout << s;
}
int main(){
cin.tie(0); ios::sync_with_stdio(0);
int T = 1, aa;
// cin >> T;aa=T;
while(T--){
// cout << "Case #" << aa-T << ": ";
solve();
}
return 0;
}
Compilation message
oneway.cpp: In function 'int main()':
oneway.cpp:124:14: warning: unused variable 'aa' [-Wunused-variable]
124 | int T = 1, aa;
| ^~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
3 ms |
4948 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
3 ms |
4948 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
3 ms |
4948 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
