// In the name of Allah
#include <bits/stdc++.h>
using namespace std;
typedef long long int ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
#define all(x) (x).begin(),(x).end()
#define len(x) ((ll) (x).size())
#define F first
#define S second
#define pb push_back
#define sep ' '
#define endl '\n'
#define Mp make_pair
#define debug(x) cerr << #x << ": " << x << endl;
#define kill(x) cout << x << '\n', exit(0);
#define set_dec(x) cout << fixed << setprecision(x);
#define file_io(x,y) freopen(x, "r", stdin); freopen(y, "w", stdout);
int n, m;
const int maxn = 1e5 + 5;
const int maxlg = 20;
vector<pii> adj[maxn];
vector<pii> ques[maxn];
pii edgs[maxn];
vector<int> oedgs, nedgs;
bool mark[maxn];
int h[maxn], mn[maxn];
pii mq[maxn];
int st[maxn], ft[maxn];
int timer = 0;
int up[maxn][maxlg];
int col[maxn]; int c = 0;
char ans[maxn], pre_ans[maxn];
bool done = 0;
void pre_dfs(int v, int i = -1) {
mark[v] = 1; mn[v] = h[v];
for (auto f : adj[v]) {
int u = f.F, j = f.S;
if (!mark[u]) {
h[u] = h[v] + 1;
pre_dfs(u, j);
mn[v] = min(mn[v], mn[u]);
}
else if (j != i) {
mn[v] = min(mn[v], h[u]);
oedgs.pb(j);
}
}
if (mn[v] >= h[v] && i != -1) nedgs.pb(i);
else if (i != -1) oedgs.pb(i);
}
void dfs_col(int v) {
mark[v] = 1; col[v] = c;
for (auto f : adj[v]) {
int u = f.F, j = f.S;
if (!mark[u]) dfs_col(u);
}
}
void pre_dfsx(int v, int p = -1) {
mark[v] = 1;
st[v] = timer++;
up[v][0] = (p != -1) ? p : v;
for (int i = 1; i < maxlg; i++) {
up[v][i] = up[up[v][i - 1]][i - 1];
}
for (auto f : adj[v]) {
int u = f.F, j = f.S;
if (!mark[u]) pre_dfsx(u, v);
}
ft[v] = timer++;
}
bool is_gr(int u, int v) {
return (st[u] <= st[v] && ft[u] >= ft[v]);
}
int get_lca(int v, int u) {
if (is_gr(v, u)) return v;
if (is_gr(u, v)) return u;
for (int i = maxlg - 1; i >= 0; i--) {
if (!is_gr(up[u][i], v)) u = up[u][i];
}
return up[u][0];
}
void solve_dfs(int v, int x, int i = -1) {
mark[v] = 1;
if (v == x) {
done = 1;
return ;
}
for (auto f : adj[v]) {
int u = f.F, j = f.S;
if (!mark[u]) {
if (v == col[edgs[j].F]) ans[j] = 'R';
else ans[j] = 'L';
solve_dfs(u, x, j);
if (done) return ;
ans[j] = pre_ans[j];
}
}
}
int main() {
ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
cin >> n >> m;
for (int i = 0; i < m; i++) {
int u, v;
cin >> u >> v; u--; v--;
if (u != v) {
adj[u].pb(Mp(v, i)); adj[v].pb(Mp(u, i));
edgs[i] = Mp(u, v);
}
}
fill(mark, mark + n, 0);
for (int i = 0; i < n; i++) {
if (!mark[i]) pre_dfs(i);
}
for (int i = 0; i < n; i++) adj[i].clear();
for (int i : oedgs) {
int u = edgs[i].F, v = edgs[i].S;
adj[u].pb(Mp(v, i)); adj[v].pb(Mp(u, i));
}
fill(mark, mark + n, 0);
for (int i = 0; i < n; i++) {
if (!mark[i]) {
dfs_col(i); c++;
}
}
for (int i = 0; i < n; i++) adj[i].clear();
for (int i : nedgs) {
int u = col[edgs[i].F], v = col[edgs[i].S];
adj[u].pb(Mp(v, i)); adj[v].pb(Mp(u, i));
}
fill(mark, mark + n, 0);
for (int i = 0; i < c; i++) {
if (!mark[i]) pre_dfsx(i);
}
fill(ans, ans + m, 'B');
int q;
cin >> q;
for (int i = 0; i < q; i++) {
int u, v;
cin >> u >> v; u--; v--;
u = col[u]; v = col[v];
if (u == v) continue;
fill(mark, mark + n, 0);
for (int j = 0; j < m; j++) pre_ans[j] = ans[j];
done = 0; solve_dfs(u, v);
}
for (char ch : ans) cout << ch;
cout << endl;
return 0;
}
Compilation message
oneway.cpp: In function 'void dfs_col(int)':
oneway.cpp:62:16: warning: unused variable 'j' [-Wunused-variable]
62 | int u = f.F, j = f.S;
| ^
oneway.cpp: In function 'void pre_dfsx(int, int)':
oneway.cpp:77:16: warning: unused variable 'j' [-Wunused-variable]
77 | int u = f.F, j = f.S;
| ^
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
6 ms |
5160 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
6 ms |
5160 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
결과 |
실행 시간 |
메모리 |
Grader output |
| 1 |
Incorrect |
6 ms |
5160 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
