#include <bits/stdc++.h>
#define ll long long
#define str string
#define ins insert
#define ld long double
#define pb push_back
#define pf push_front
#define pof pop_front()
#define pob pop_back()
#define lb lower_bound
#define ub upper_bound
#define endl "\n"
#define fr first
#define sc second
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define sz size()
#define vll vector<ll>
#define bc back()
#define arr array
#define pll vector<pair<ll,ll>>
using namespace std;/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ordered_set tree<ll, null_type,less_equal<ll>, rb_tree_tag,tree_order_statistics_node_update>*/
template<class S,class T>
bool chmin(S &a,const T &b) {
return a>b?(a=b)==b:false;
}
template<class S,class T>
bool chmax(S &a,const T &b) {
return a<b?(a=b)==b:false;
}
//void fre(string s){freopen((s+".in").c_str(),"r",stdin);freopen((s+".out").c_str(),"w",stdout);}
void start(){
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
}
const ll inf=1e18;
const ll mod=998244353;
const ll N=1e5+5;
const ld eps=1e-9;
vector<vll> g(N),g2(N);
ll n,m;
ll d[N],up[N];
pair<ll,ll> e[N];
bool br[N];
ll comp[N];
char ans[N];
void dfs(ll v,ll x){
up[v]=d[v];
ll b;
for(auto i : g[v]){
if(i==x) continue;
if(v==e[i].fr)b=e[i].sc;
else b=e[i].fr;
if(d[b]){chmin(up[v],d[b]);continue;}
d[b]=d[v]+1;
dfs(b,i);
chmin(up[v],up[b]);
}
if(up[v]>=d[v]){
br[x]=1;
}
chmin(up[v],d[v]-1);
}
void build(ll v,ll x){
ll b;
for(auto i : g[v]){
if(v==e[i].fr)b=e[i].sc;
else b=e[i].fr;
if(d[b]<=d[v] || comp[b])continue;
if(br[i]){
comp[b]=b;
}
else comp[b]=comp[v];
build(b,i);
}
}
ll c[N],c2[N];
void dfs2(ll v,ll x){
ll b;
for(auto i : g2[v]){
if(i==x) continue;
if(v==e[i].fr)b=e[i].sc;
else b=e[i].fr;
if(d[b]<=d[v]) continue;
d[x]=d[v]+1;
dfs2(b,i);
c[v]+=c[b];
c2[v]+=c2[b];
}
if(c[v]==c2[v])ans[x]='B';
else if(c[v]<c2[v]){
if(e[x].fr==v)ans[x]='L';
else ans[x]='R';
}else{
if(e[x].fr==v)ans[x]='R';
else ans[x]='L';
}
}
void solve(){
ll i,j;
ll q;
cin>>n>>m;
ll a,b;
for(i=1;i<=m;i++){
cin>>a>>b;
e[i]={a,b};
if(a==b) continue;
g[a].pb(i);
g[b].pb(i);
}
d[1]=1;
dfs(1,0);
comp[1]=1;
build(1,0);
for(i=1;i<=m;i++){
a=e[i].fr,b=e[i].sc;
if(!br[i])ans[i]='B';
else {
e[i].fr=comp[e[i].fr],e[i].sc=comp[e[i].sc];
g2[comp[a]].pb(i);
g2[comp[b]].pb(i);
}
}
d[1]=0;
cin>>q;
for(i=1;i<=m;i++)ans[i]=0;
for(i=1;i<=q;i++){
cin>>a>>b;
c[comp[a]]++;
c2[comp[b]]++;
}
dfs2(1,0);
for(i=1;i<=m;i++) cout<<(ans[i]==0 ? 'B' : ans[i]);
}
signed main(){
start();
ll t=1;
//cin>>t;
while(t--) solve();
return 0;
}
/*
9 10
1 2
2 1
1 3
3 4
4 5
3 5
4 6
2 7
2 8
8 9
2
7 5
9 6
*/
Compilation message
oneway.cpp: In function 'void solve()':
oneway.cpp:105:10: warning: unused variable 'j' [-Wunused-variable]
105 | ll i,j;
| ^
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
3 ms |
9052 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
3 ms |
9052 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
3 ms |
9052 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
