#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 low[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 dfs_lca(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;
dfs_lca(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_low(int v, int p){
used[v] = true;
tin[v] = low[v] = ++timer;
for (auto u : g[v]){
if (u == p) continue;
if (used[u]){
low[v] = min(low[v], tin[u]);
}else{
dfs_low(u, v);
low[v] = min(low[v], low[u]);
if (low[u] > tin[v]){
brid[{v, u}] = 1;
brid[{u, 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_low(i, i);
}
for(int i = 1; i <= n; i++){
if(lead[i] == 0){
lead[i] = i;
dfsc(i);
}
}
set <pair <int,int> > st;
for(auto x : road){
if(brid.count(x)){
if(st.find(x) != st.end())return EXIT_FAILURE;
st.insert(x);
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){
dfs_lca(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:85:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
85 | main(){
| ^~~~
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
2 ms |
11096 KB |
Output is correct |
| 2 |
Runtime error |
2 ms |
6748 KB |
Execution failed because the return code was nonzero |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
2 ms |
11096 KB |
Output is correct |
| 2 |
Runtime error |
2 ms |
6748 KB |
Execution failed because the return code was nonzero |
| 3 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Correct |
2 ms |
11096 KB |
Output is correct |
| 2 |
Runtime error |
2 ms |
6748 KB |
Execution failed because the return code was nonzero |
| 3 |
Halted |
0 ms |
0 KB |
- |
