#pragma GCC optimize("Ofast,unroll-loops")
#pragma GCC target("avx,avx2,fma")
#include <bits/stdc++.h>
#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
using namespace std;
int pow(int a,int b,int m){int ans=1;while(b){if(b&1){ans=(ans*a)%m;}b>>=1;a=(a*a)%m;}return ans;}
int binpow(int a,int b){int ans=1;while(b){if(b&1){ans=(ans*a);}b>>=1;a=(a*a);}return ans;}
const int N = 1e5 + 10;
int fup[N], h[N];
vector <int> g[N];
vector <int> gc[N];
int lead[N];
int vis[N], par[N];
int tin[N], tout[N], up[N][25], used[N];
int timer;
map <pair <int,int>, int > brid;
void dfsc(int v){
vis[v] = 1;
for(auto to : g[v]){
if(vis[to] == 0 && !brid.count({v, to})){
lead[to] = lead[v];
dfsc(to);
}
}
}
void dfs2(int v, int p = 1) {
tin[v] = ++timer;
par[v] = p;
up[v][0] = p;
for (int i=1; i<=20; ++i)
up[v][i] = up[up[v][i-1]][i-1];
for (auto to : gc[v]) {
if (to == p)continue;
assert(par[to] == 0);
//cout <<p<<"->"<< v <<"->" << to << endl;
dfs2 (to, v);
}
tout[v] = ++timer;
}
bool upper (int a, int b) {
return tin[a] <= tin[b] && tout[a] >= tout[b];
}
int lca (int a, int b) {
if (upper (a, b)) return a;
if (upper (b, a)) return b;
for (int i=20; i>=0; --i)
if (! upper (up[a][i], b))
a = up[a][i];
return up[a][0];
}
void dfs (int v, int p = -1) {
used[v] = true;
tin[v] = fup[v] = timer++;
for (size_t i=0; i<g[v].size(); ++i) {
int to = g[v][i];
if (to == p) continue;
if (used[to])
fup[v] = min (fup[v], tin[to]);
else {
dfs (to, v);
fup[v] = min (fup[v], fup[to]);
if (fup[to] > tin[v]){
brid[{v, to}] = 1;
brid[{to, v}] = 1;
}
}
}
}
main(){
iostream::sync_with_stdio(false);
cin.tie(nullptr);
cout.tie(nullptr);
int n, m;
cin >> n >> m;
vector <pair <int,int> > road;
for(int i = 0; i < m; i++){
int a, b;
cin >> a >> b;
g[a].pb(b);
g[b].pb(a);
road.pb({a, b});
}
for(int i = 1; i<= n; i++){
if(!used[i])dfs(i, i);
}
for(int i = 1; i <= n; i++){
if(vis[i] == 0){
lead[i] = i;
dfsc(i);
}
}
for(auto x : road){
if(brid.count(x)){
//cout << "===" << x.ff <<" "<< x.ss <<" "<< lead[x.ff] <<" "<< lead[x.ss]<< endl;
gc[lead[x.ff]].pb(lead[x.ss]);
gc[lead[x.ss]].pb(lead[x.ff]);
}
}
memset(used, 0, sizeof(used));
for(int i = 1; i <= n; i++){
if(par[i] == 0){
dfs2(i, i);
}
}
int p;
cin >> p;
map <pair <int,int>, int> mp;
while(p--){
int a, b;
cin >> a >> b;
a = lead[a];
b = lead[b];
if(a == b)continue;
int lc = lca(a, b);
while(a != lc){
//cout << "--"<<a << endl;
if(par[a] == 0)return EXIT_FAILURE;
mp[{lead[a], par[lead[a]]}] = 1;
a = par[lead[a]];
}
while(b != lc){
//cout << "---" << b <<" "<< par[b]<< endl;
if(par[b] == 0)return EXIT_FAILURE;
mp[{par[lead[b]], lead[b]}] = 1;
b = par[lead[b]];
}
}
for(auto x : road){
int f = x.ff, s = x.ss;
f = lead[f];
s = lead[s];
if(mp.count({f, s})){
cout << 'R';
}else if(mp.count({s, f})){
cout << 'L';
}else
cout << 'B';
}
}
Compilation message
oneway.cpp:87:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
87 | main(){
| ^~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
3 ms |
11096 KB |
Output is correct |
| 2 |
Runtime error |
14 ms |
22228 KB |
Execution killed with signal 6 |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
3 ms |
11096 KB |
Output is correct |
| 2 |
Runtime error |
14 ms |
22228 KB |
Execution killed with signal 6 |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Correct |
3 ms |
11096 KB |
Output is correct |
| 2 |
Runtime error |
14 ms |
22228 KB |
Execution killed with signal 6 |
| 3 |
Halted |
0 ms |
0 KB |
- |
