#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef tree<int, null_type, less<int>, rb_tree_tag,tree_order_statistics_node_update> ordered_set;
#define scan(x) do{while((x=getchar())<'0'); for(x-='0'; '0'<=(_=getchar()); x=(x<<3)+(x<<1)+_-'0');}while(0)
char _;
#define complete_unique(a) a.erase(unique(a.begin(),a.end()),a.end())
#define all(a) a.begin(),a.end()
#define println printf("\n");
#define readln(x) getline(cin,x);
#define pb push_back
#define endl "\n"
#define INT_INF 0x3f3f3f3f
#define LL_INF 0x3f3f3f3f3f3f3f3f
#define MOD 1000000007
#define mp make_pair
#define fastio cin.tie(0); cin.sync_with_stdio(0);
#define MAXN 100005
#define MAXM 100005
#define LOGN 20
typedef unsigned long long ull;
typedef long long ll;
typedef long double ld;
typedef unordered_map<int,int> umii;
typedef pair<int,int> pii;
typedef pair<double,double> pdd;
typedef pair<ll,ll> pll;
typedef pair<int,pii> triple;
typedef int8_t byte;
mt19937 g1(time(0));
int randint(int a, int b){return uniform_int_distribution<int>(a, b)(g1);}
ll randlong(ll a,ll b){return uniform_int_distribution<long long>(a, b)(g1);}
ll gcd(ll a, ll b){return b == 0 ? a : gcd(b, a % b);}
ll lcm(ll a, ll b){return a*b/gcd(a,b);}
ll fpow(ll b, ll exp, ll mod){if(exp == 0) return 1;ll t = fpow(b,exp/2,mod);if(exp&1) return t*t%mod*b%mod;return t*t%mod;}
ll divmod(ll i, ll j, ll mod){i%=mod,j%=mod;return i*fpow(j,mod-2,mod)%mod;}
int num_nodes,num_edges,num_q,dlow[MAXN],dnum[MAXN],par[MAXN],par2[MAXN],par_e[MAXN],group[MAXN],path[MAXN],depth[MAXN],st[MAXN][LOGN],up[MAXN],down[MAXN],ans[MAXM],ncnt,scnt;
bool is_bridge[MAXM],vis[MAXN],isrt[MAXN];
vector<pii> bc[MAXN],g2[MAXN];
vector<pii> edges;
void tarjans(int node){
dlow[node] = dnum[node] = ++ncnt;
for(pii check:bc[node]){
if(dnum[check.first] == 0){
par[check.first] = node;
tarjans(check.first);
if(dlow[check.first] > dnum[node])
is_bridge[check.second] = true;
dlow[node] = min(dlow[node],dlow[check.first]);
}else if(check.first != par[node])
dlow[node] = min(dlow[node],dnum[check.first]);
}
}
void build_graph(int node){
int curr = ++scnt;
queue<int> q;
q.push(node);
vis[node] = true;
while(q.size()){
int n = q.front(); q.pop();
group[n] = curr;
for(pii check:bc[n]){
if(vis[check.first]) continue;
if(is_bridge[check.second]){
build_graph(check.first);
g2[curr].pb(mp(group[check.first],check.second));
g2[group[check.first]].pb(mp(curr,check.second));
}else{
vis[check.first] = true;
q.push(check.first);
}
}
}
}
void dfs(int node, int prev, int d){
path[d] = node;
depth[node] = d;
for(pii check:g2[node]){
if(check.first == prev) continue;
par_e[check.first] = check.second;
par2[check.first] = node;
dfs(check.first,node,d+1);
}
for(int i=0; i<LOGN; i++){
int nxt = 1<<i;
if(d < nxt) break;
st[node][i] = path[d-nxt];
}
}
int lca(int a, int b){
if(depth[a] > depth[b]) swap(a,b);
int diff = depth[b]-depth[a];
for(int i=0; i<LOGN; i++)
if(diff&(1<<i))
b = st[b][i];
if(a == b) return a;
for(int i=LOGN-1; i>=0; i--)
if(st[a][i] != -1 && st[b][i] != -1 && st[a][i] != st[b][i])
a = st[a][i], b = st[b][i];
return st[a][0];
}
void solve(int node, int prev){
vis[node] = true;
for(pii check:g2[node]){
if(check.first == prev) continue;
solve(check.first,node);
up[node]+=up[check.first];
down[node]+=down[check.first];
}
assert(!(up[node]&&down[node]));
if(up[node]) ans[par_e[node]] = 1;
else if(down[node]) ans[par_e[node]] = 2;
}
int main(){
scanf("%d %d",&num_nodes,&num_edges);
for(int i=1; i<=num_edges; i++){
int a,b; scanf(" %d %d",&a,&b);
bc[a].pb(mp(b,i));
bc[b].pb(mp(a,i));
edges.pb(mp(a,b));
}
for(int i=1; i<=num_nodes; i++){
if(vis[i]) continue;
tarjans(i);
build_graph(i);
dfs(group[i],-1,0);
isrt[group[i]] = true;
}
// for(int i=1; i<=num_nodes; i++) printf("%d ",group[i]); printf("\n");
scanf(" %d",&num_q);
for(int i=1; i<=num_q; i++){
int a,b,lc; scanf(" %d %d",&a,&b);
a = group[a], b = group[b], lc = lca(a,b);
up[a]++, up[lc]--;
down[b]++, down[lc]--;
}
memset(vis,false,sizeof vis);
for(int i=1; i<=scnt; i++){
if(!isrt[i]) continue;
solve(i,-1);
}
// printf("%d %d\n",up[10],down[10]);
// printf("%d\n",par2[9]);
for(int i=1; i<=num_edges; i++){
// printf("%d ",ans[i]);
int a = group[edges[i-1].first], b = group[edges[i-1].second];
if(ans[i] == 0) printf("B");
else if(ans[i] == 1){
if(par2[a] == b) printf("R");
else printf("L");
}else{
if(par2[a] == b) printf("L");
else printf("R");
}
}
}
/*
4 4
1 2
2 3
2 4
3 4
2
1 3
1 4
ans=RBBB
*/
Compilation message
oneway.cpp: In function 'int main()':
oneway.cpp:131:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf("%d %d",&num_nodes,&num_edges);
~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
oneway.cpp:133:17: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
int a,b; scanf(" %d %d",&a,&b);
~~~~~^~~~~~~~~~~~~~~~
oneway.cpp:146:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
scanf(" %d",&num_q);
~~~~~^~~~~~~~~~~~~~
oneway.cpp:148:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
int a,b,lc; scanf(" %d %d",&a,&b);
~~~~~^~~~~~~~~~~~~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
7 ms |
5240 KB |
Output is correct |
| 2 |
Correct |
6 ms |
5112 KB |
Output is correct |
| 3 |
Correct |
8 ms |
5240 KB |
Output is correct |
| 4 |
Correct |
7 ms |
5368 KB |
Output is correct |
| 5 |
Correct |
8 ms |
5624 KB |
Output is correct |
| 6 |
Correct |
7 ms |
5352 KB |
Output is correct |
| 7 |
Correct |
9 ms |
5624 KB |
Output is correct |
| 8 |
Correct |
7 ms |
5368 KB |
Output is correct |
| 9 |
Incorrect |
7 ms |
5240 KB |
Output isn't correct |
| 10 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
7 ms |
5240 KB |
Output is correct |
| 2 |
Correct |
6 ms |
5112 KB |
Output is correct |
| 3 |
Correct |
8 ms |
5240 KB |
Output is correct |
| 4 |
Correct |
7 ms |
5368 KB |
Output is correct |
| 5 |
Correct |
8 ms |
5624 KB |
Output is correct |
| 6 |
Correct |
7 ms |
5352 KB |
Output is correct |
| 7 |
Correct |
9 ms |
5624 KB |
Output is correct |
| 8 |
Correct |
7 ms |
5368 KB |
Output is correct |
| 9 |
Incorrect |
7 ms |
5240 KB |
Output isn't correct |
| 10 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
7 ms |
5240 KB |
Output is correct |
| 2 |
Correct |
6 ms |
5112 KB |
Output is correct |
| 3 |
Correct |
8 ms |
5240 KB |
Output is correct |
| 4 |
Correct |
7 ms |
5368 KB |
Output is correct |
| 5 |
Correct |
8 ms |
5624 KB |
Output is correct |
| 6 |
Correct |
7 ms |
5352 KB |
Output is correct |
| 7 |
Correct |
9 ms |
5624 KB |
Output is correct |
| 8 |
Correct |
7 ms |
5368 KB |
Output is correct |
| 9 |
Incorrect |
7 ms |
5240 KB |
Output isn't correct |
| 10 |
Halted |
0 ms |
0 KB |
- |
