#include<bits/stdc++.h>
#define all(a) a.begin(),a.end()
#define pb push_back
#define int long long
using namespace std ;
const int maxn = 5e6 + 10 , maxq = 502 , inf = 1e9 , mod = 1e9+7 ;
vector <pair <int , int > > G[maxn] ;
vector <int> l[maxn] ;
int dp[maxn] , mark2[maxn] , mark[maxn] , par[maxn] , cnt = 1 ,c[maxn] , st[maxn] , en[maxn] , pr[maxn] , pp[maxn] , ans[maxn] , ok[maxn];
pair <int , int > ed[maxn] ;
void dfs(int v){
mark[v] = 1;
for(int i = 0; i < (int)G[v].size() ; i++){
int u = G[v][i].first , id = G[v][i].second ;
if(mark[u] == 1){
if(mark2[id] == 0){
dp[v] ++ ;
dp[u] -- ;
ans[id] = 3 ;
mark2[id] = 1;
}
continue ;
}
mark2[id] = 1;
par[u] = id ;
dfs(u) ;
dp[v]+=dp[u];
}
}
void dfs2(int v , int r){
mark[v] = 1;
c[v] = r ;
for(int i = 0; i < (int)G[v].size() ; i++){
int u = G[v][i].first , id = G[v][i].second ;
if(mark[u] == 1)continue ;
if(dp[u] == 0){
cnt ++;
//cout << v << " " << u << "<---\n";
pr[cnt] = id ;
pp[cnt] = r ;
l[r].pb(cnt);
dfs2(u , cnt);
}else{
dfs2(u , r);
}
}
}
vector <int> vv[maxn] , uu[maxn] ;
int sec = 1 ;
void dfs3(int v){
mark[v] = 1;
for(int i = 0 ;i < (int)l[v].size() ; i++){
int u = l[v][i] ;
dfs3(u);
}
if(pp[v] == 0)return ;
int ok = 0 ;
vector <int> xx , yy ;
sort(all(vv[v]));sort(all(uu[v]));
while(vv[v].size() > 0 && uu[v].size() > 0){
int vx = vv[v].back() , vz = uu[v].back() ;
if(vx == vz){
vv[v].pop_back();
uu[v].pop_back();
}else if(vx > vz){
vv[pp[v]].pb(vx);
xx.pb(vx);
vv[v].pop_back();
}else{
yy.pb(vz);
uu[pp[v]].pb(vz);
uu[v].pop_back();
}
}
while(vv[v].size() > 0){
int vx = vv[v].back(); vv[v].pop_back();
xx.pb(vx);
vv[pp[v]].pb(vx);
}
while(uu[v].size() > 0){
int vx = uu[v].back() ; uu[v].pop_back();
yy.pb(vx);
uu[pp[v]].pb(vx);
}
int id = pr[v];
if(xx.size() == 0 && yy.size() ==0 ){
ans[pr[v]] = 3 ;
}else if (yy.size() == 0){
if(c[ed[id].first] == v){
ans[id] = 2 ;
}else{
ans[id] = 1 ;
}
}else{
if(c[ed[id].first] == v){
ans[id] = 1 ;
}else{
ans[id] = 2 ;
}
}
uu[v].clear();
vv[v].clear();
}
signed main(){
ios::sync_with_stdio(false); cin.tie(0);cout.tie(0);
int n , m ;
cin >> n >> m ;
for(int i =1 ;i <= m ; i++){
int v , u ;
cin >> v >> u ;
if(v==u){
ans[i] = 3;
continue ;
}
G[v].pb({u,i});
G[u].pb({v,i});
ed[i] = {v , u} ;
}
for(int i = 1; i <= n ; i++){
if(mark[i] == 1)continue ;
dfs(i);
}
for(int i =1 ; i <= n ; i++){
if(par[i] == 0)continue ;
if(dp[i] >= 1){
ans[par[i]] = 3 ;
}
}
memset(mark , 0 , sizeof mark);
memset(mark2 , 0 , sizeof mark2);
vector <int> vec ;
for(int i =1; i <= n ; i ++){
if(mark[i] == 1)continue ;
vec.pb(cnt);
dfs2(i ,cnt ) ;
cnt++;
}
memset(mark , 0 , sizeof mark);
int q ;
cin >> q ;
while(q--){
int v , u ;
cin >> v >> u ;
if(c[v] == c[u])continue ;
vv[c[v]].pb(q);
uu[c[u]].pb(q);
}
for(int i =0 ; i < (int)vec.size() ;i++){
int u = vec[i];
dfs3(u);
}
for(int i = 1 ; i <= m ; i++){
if(ans[i] == 3){
cout << "B";
}
if(ans[i] == 2){
cout << "R";
}
if(ans[i] == 1){
cout << "L" ;
}
}
cout << endl;
}
Compilation message
oneway.cpp: In function 'void dfs3(long long int)':
oneway.cpp:59:6: warning: unused variable 'ok' [-Wunused-variable]
59 | int ok = 0 ;
| ^~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
106 ms |
262144 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
106 ms |
262144 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
106 ms |
262144 KB |
Execution killed with signal 9 |
| 2 |
Halted |
0 ms |
0 KB |
- |
