#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;
template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl
#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)
template<typename T>
void amin(T &a, T b) {
a = min(a,b);
}
template<typename T>
void amax(T &a, T b) {
a = max(a,b);
}
#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif
/*
*/
const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
vector<array<int,3>> adj1[N];
vector<bool> vis(N);
vector<bool> bridge(N);
vector<int> tin(N), low(N);
int timer = 1;
void dfs1(int u, int pid){
vis[u] = 1;
tin[u] = low[u] = timer++;
for(auto [v,id,dir] : adj1[u]){
if(id == pid) conts;
if(vis[v]){
amin(low[u],tin[v]);
}
else{
dfs1(v,id);
amin(low[u],low[v]);
if(low[v] > tin[u]){
bridge[id] = 1;
}
}
}
}
vector<int> col(N);
void dfs2(int u, int c){
vis[u] = 1;
col[u] = c;
for(auto [v,id,dir] : adj1[u]){
if(vis[v]) conts;
if(bridge[id]) conts;
dfs2(v,c);
}
}
vector<pii> adj2[N];
struct lca_algo {
// LCA template (for graphs with 1-based indexing)
int LOG = 1;
vector<int> depth;
vector<vector<int>> up;
vector<int> tin, tout;
vector<int> pid;
int timer = 1;
lca_algo() {
}
lca_algo(int n) {
lca_init(n);
}
void lca_init(int n) {
while ((1 << LOG) < n) LOG++;
up = vector<vector<int>>(n + 1, vector<int>(LOG, 1));
depth = vector<int>(n + 1);
tin = vector<int>(n + 1);
tout = vector<int>(n + 1);
pid = vector<int>(n + 1);
lca_dfs(1, -1);
}
void lca_dfs(int node, int par) {
tin[node] = timer++;
for(auto [child, id] : adj2[node]) {
if (child == par) conts;
up[child][0] = node;
rep1(j, LOG - 1) {
up[child][j] = up[up[child][j - 1]][j - 1];
}
depth[child] = depth[node] + 1;
pid[child] = id;
lca_dfs(child, node);
}
tout[node] = timer-1;
}
int lift(int u, int k) {
rep(j, LOG) {
if (k & (1 << j)) {
u = up[u][j];
}
}
return u;
}
int query(int u, int v) {
if (depth[u] < depth[v]) swap(u, v);
int k = depth[u] - depth[v];
u = lift(u, k);
if (u == v) return u;
rev(j, LOG - 1, 0) {
if (up[u][j] != up[v][j]) {
u = up[u][j];
v = up[v][j];
}
}
u = up[u][0];
return u;
}
int get_dis(int u, int v) {
int lca = query(u, v);
return depth[u] + depth[v] - 2 * depth[lca];
}
bool is_ances(int u, int v){
return tin[u] <= tin[v] and tout[u] >= tout[v];
}
};
void solve(int test_case)
{
int n,m; cin >> n >> m;
vector<pii> edges(m+5);
rep1(i,m){
int u,v; cin >> u >> v;
edges[i] = {u,v};
adj1[u].pb({v,i,0}), adj1[v].pb({u,i,1});
}
int k; cin >> k;
vector<pii> a(k+5);
rep1(i,k) cin >> a[i].ff >> a[i].ss;
dfs1(1,-1);
rep1(i,n){
assert(vis[i]);
}
fill(all(vis),0);
int ptr = 0;
rep1(u,n){
if(vis[u]) conts;
dfs2(u,++ptr);
}
rep1(u,n){
for(auto [v,id,dir] : adj1[u]){
if(dir) conts;
if(col[u] != col[v]){
int cu = col[u], cv = col[v];
adj2[cu].pb({cv,id}), adj2[cv].pb({cu,id});
edges[id] = {cu,cv};
}
}
}
lca_algo LCA(ptr);
vector<char> ans(m+5);
rep1(i,m) ans[i] = 'B';
rep1(i,k){
auto [u,v] = a[i];
u = col[u], v = col[v];
int lca = LCA.query(u,v);
while(u != lca){
int p = LCA.up[u][0];
int id = LCA.pid[u];
if(u == edges[id].ff){
ans[id] = 'R';
}
else{
ans[id] = 'L';
}
u = p;
}
while(v != lca){
int p = LCA.up[v][0];
int id = LCA.pid[v];
if(v == edges[id].ff){
ans[id] = 'L';
}
else{
ans[id] = 'R';
}
v = p;
}
}
rep1(i,m) cout << ans[i];
cout << endl;
}
int main()
{
fastio;
int t = 1;
// cin >> t;
rep1(i, t) {
solve(i);
}
return 0;
}
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
9 ms |
12380 KB |
Execution killed with signal 6 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
9 ms |
12380 KB |
Execution killed with signal 6 |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Runtime error |
9 ms |
12380 KB |
Execution killed with signal 6 |
| 2 |
Halted |
0 ms |
0 KB |
- |
