#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pll pair<long long, long long>
#define pb push_back
#define F first
#define S second
#define all(x) (x).begin(), (x).end()
const ll N = 2e5 + 100;
const ll inf = 1e18;
const ll mod = 1e9 + 7;
const ll block = 480;
ll n,m,p,timer=0;
vector<pll>adj[N];
struct ccjv{ll v, prv, nxt;};
vector<ccjv>g[N];
ll cmp[N], low[N], num[N], b[N], pa[N], up[N][20], dep[N], d[N];
pll edge[N];
ll cur = 0;
vector<pll>order;
map<pll,ll>dir;
void pre_dfs(ll u, ll par){
low[u] = num[u] = ++timer;
for(auto x : adj[u]){
ll v = x.F, idx = x.S;
if(idx == par) continue;
if(num[v]) low[u] = min(low[u], num[v]);
else{
pre_dfs(v, idx);
low[u] = min(low[u], low[v]);
if(low[v] == num[v]) {
//cout << "bridge" << ' ' << u << ' ' << v << '\n';
b[idx] = 1;
}
}
}
}
void dfs_cmp(ll u, ll par){
cmp[u] = cur;
for(auto x : adj[u]){
ll v = x.F, idx = x.S;
if(idx == par) continue;
if(b[idx]){
if(cmp[v]) g[cmp[u]].pb({cmp[v], u, v}), g[cmp[v]].pb({cmp[u], v, u});
}
else if(!cmp[v]) dfs_cmp(v, idx);
}
}
ll lca(ll u, ll v){
if(dep[u] != dep[v]){
if(dep[u] < dep[v]) swap(u, v);
ll k = dep[u] - dep[v];
for(int i = 19; i >= 0;i--){
if(k & (1 << i)) u = up[u][i];
}
}
if(u == v) return u;
for(int i = 19; i >= 0;i--){
if(up[u][i] != up[v][i]) u = up[u][i], v = up[v][i];
}
return up[u][0];
}
void dfs_build(ll u, ll par){
for(auto x : g[u]){
ll v = x.v;
if(v == par) continue;
up[v][0] = u;
for(int i = 1; i <= 19;i++) up[v][i] = up[up[v][i-1]][i-1];
dep[v] = dep[u] + 1;
dfs_build(v, u);
}
}
void dfs(ll u, ll par){
for(auto x : g[u]){
ll v = x.v;
if(v == par) continue;
dfs(v, u);
d[u] += d[v];
}
for(auto x : g[u]){
ll v = x.v;
if(v == par) continue;
if(d[v] < 0) dir[{x.nxt, x.prv}] = 1, dir[{x.prv, x.nxt}] = -1;
else if(d[v] > 0) dir[{x.nxt, x.prv}] = -1, dir[{x.prv, x.nxt}] = 1;
}
}
void to_thic_cau(){
cin >> n >> m;
for(int i = 1; i <= m;i++){
ll u,v; cin >> u >> v;
edge[i] = {u, v};
adj[u].pb({v, i});
adj[v].pb({u, i});
}
for(int i = 1; i <= n;i++) if(!num[i]) pre_dfs(i, 0);
for(int i = 1; i <= n;i++){
if(!cmp[i]){
++cur;
dfs_cmp(i, 0);
}
}
dfs_build(cmp[1], 0);
cin >> p;
for(int i = 1; i <= p;i++){
ll a,b; cin >> a >> b;
a = cmp[a], b = cmp[b];
ll x = lca(a, b);
if(x != a && x != b){
d[a]--, d[x]++;
d[b]++, d[x]--;
}
else if(x == a){
d[b]--, d[a]++;
}
else if(x == b) d[a]--, d[b]++;
}
dfs(cmp[1], 0);
for(int i = 1; i <= m;i++){
if(!b[i]){
cout << 'B';
}
else{
if(!dir[{edge[i].F, edge[i].S}]) cout << 'B';
else if(dir[{edge[i].F, edge[i].S}] == 1) cout << 'R';
else cout << 'L';
}
}
cout << '\n';
}
signed main(){
ios_base::sync_with_stdio(0);
cin.tie(0);
ll tc = 1;
//cin >> tc;
while(tc--) to_thic_cau();
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
15964 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
15964 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
2 ms |
15964 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
