#include <algorithm>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <functional>
#include <iomanip>
#include <iostream>
#include <iterator>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <unordered_map>
#include <unordered_set>
#include <vector>
#ifdef DEBUG
#include <time.h>
#endif
#define all(a) (a).begin(), (a).end()
#define rev(a) (a).rbegin(), (a).rend()
#define F first
#define S second
int recur_depth = 0;
#ifdef DEBUG
#define dbg(x) \
{ \
++recur_depth; \
auto x_ = x; \
--recur_depth; \
cerr << string(recur_depth, '\t') << "\e[91m" << __func__ << ":" \
<< __LINE__ << "\t" << #x << " = " << x_ << "\e[39m" << endl; \
}
#else
#define dbg(x)
#endif
using namespace std;
using namespace __gnu_pbds;
typedef pair<int, int> ii;
typedef long long ll;
typedef long double ld;
typedef pair<ll, ll> llll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<pair<int, int>> vii;
typedef vector<vii> vvii;
typedef vector<ll> vl;
typedef vector<vl> vvl;
typedef vector<pair<ll, ll>> vll;
typedef vector<vll> vvll;
typedef vector<bool> vb;
template <class type1>
using ordered_set = tree<type1, null_type, less<type1>, rb_tree_tag,
tree_order_statistics_node_update>;
template <typename A, typename B>
ostream &operator<<(ostream &os, const pair<A, B> &p) {
return os << '(' << p.first << ", " << p.second << ')';
}
template <typename T_container, typename T = typename enable_if<
!is_same<T_container, string>::value,
typename T_container::value_type>::type>
ostream &operator<<(ostream &os, const T_container &v) {
os << '{';
string sep;
for (const T &x : v)
os << sep << x, sep = ", ";
return os << '}';
}
const ll MOD = 1e9 + 7;
// const ll MOD = 998244353;
const ll INF = 1e9;
const ld EPS = 1e-9;
struct DSU {
int n;
vi par, sz;
DSU(int n) : n(n), par(vi(n, -1)), sz(vi(n, 1)) {}
int find(int u) {
if (par[u] == -1)
return u;
return par[u] = find(par[u]);
}
void merge(int u, int v) {
u = find(u), v = find(v);
if (u == v)
return;
if (sz[u] < sz[v])
swap(u, v);
par[v] = u;
sz[u] += sz[v];
}
};
struct ST {
int n;
vvii st;
vi lg2;
const int MAXLG = 22;
ST(int n, vii a) : n(n) {
st = vvii(MAXLG, vii(n));
st[0] = a;
for (int j = 1; j < MAXLG; j++)
for (int i = 0; i + (1 << j) <= n; i++)
st[j][i] = min(st[j - 1][i], st[j - 1][i + (1 << (j - 1))]);
lg2 = vi(n + 10);
lg2[1] = 0;
for (int i = 2; i < lg2.size(); i++)
lg2[i] = lg2[i / 2] + 1;
}
int query(int l, int r) {
int k = lg2[r - l + 1];
return min(st[k][l], st[k][r - (1 << k) + 1]).second;
}
};
void solve() {
struct Ed {
int u, v, idx;
bool is_bridge;
int res;
};
int n, m;
cin >> n >> m;
vvii adj(n);
vector<Ed> eds;
for (int i = 0; i < m; i++) {
int u, v;
cin >> u >> v;
u--, v--;
adj[u].push_back({v, i});
if (u != v)
adj[v].push_back({u, i});
eds.push_back(Ed{u, v, i, 0, 2});
}
int p;
cin >> p;
vii imp(p);
for (auto &[x, y] : imp)
cin >> x >> y, x--, y--;
int timer = 0;
vb vis(n);
vi tin(n, -1), low(n, -1);
function<void(int, int)> f = [&](int u, int u_par_ed_id) {
vis[u] = 1;
tin[u] = low[u] = timer++;
for (auto [v, i] : adj[u])
if (i != u_par_ed_id) {
if (vis[v])
low[u] = min(low[u], low[v]);
else {
f(v, i);
low[u] = min(low[u], low[v]);
if (low[v] > tin[u])
eds[i].is_bridge = 1;
}
}
};
for (int i = 0; i < n; i++)
if (!vis[i])
f(i, -1);
DSU d(n);
for (auto &ed : eds)
if (!ed.is_bridge) {
d.merge(ed.u, ed.v);
}
vvii tree(n);
for (auto &ed : eds)
if (ed.is_bridge) {
tree[d.find(ed.u)].push_back({d.find(ed.v), ed.idx});
tree[d.find(ed.v)].push_back({d.find(ed.u), ed.idx});
}
int root = d.find(0);
vii par_tree(n, {-2, -2});
vi cnt_child(n, -1);
vi depth(n, -1);
vii euler;
vi first_occ(n);
function<void(int, int)> g = [&](int u, int p) {
if (p == -1)
par_tree[u] = {-1, -1}, depth[u] = 0;
cnt_child[u] = 0;
first_occ[u] = euler.size();
euler.push_back({depth[u], u});
for (auto [v, i] : tree[u])
if (v != p) {
par_tree[v] = {u, i};
depth[v] = depth[u] + 1;
cnt_child[u]++;
g(v, u);
euler.push_back({depth[u], u});
}
};
g(root, -1);
ST st(euler.size(), euler);
vii cnt_imp(n);
for (auto [x, y] : imp) {
x = d.find(x), y = d.find(y);
if (x == y)
continue;
int lca = st.query(first_occ[x], first_occ[y]);
cnt_imp[x].first++, cnt_imp[y].second++;
cnt_imp[lca].first--, cnt_imp[lca].second--;
}
queue<int> q;
for (int i = 0; i < n; i++)
if (cnt_child[i] == 0)
q.push(i);
while (!q.empty()) {
int u = q.front();
q.pop();
// cerr << "U: " << u << "\n";
// cerr << "\tCn: " << cnt_imp[u] << "\n";
auto [p, pe_id] = par_tree[u];
if (p < 0)
continue;
// assert(cnt_imp[u].first == 0 || cnt_imp[u].second == 0);
if (cnt_imp[u].first > 0) {
if (eds[pe_id].u == u)
eds[pe_id].res = 0;
else
eds[pe_id].res = 1;
}
if (cnt_imp[u].second > 0) {
if (eds[pe_id].u == u)
eds[pe_id].res = 1;
else
eds[pe_id].res = 0;
}
cnt_imp[p].first += cnt_imp[u].first;
cnt_imp[p].second += cnt_imp[u].second;
if (--cnt_child[p] == 0)
q.push(p);
}
for (int i = 0; i < m; i++) {
if (eds[i].res == 2)
cout << "B";
if (eds[i].res == 0)
cout << "R";
if (eds[i].res == 1)
cout << "L";
}
cout << "\n";
}
int main() {
ios_base::sync_with_stdio(0);
cin.tie(NULL);
clock_t start = clock();
int test_cases = 1;
// cin >> test_cases;
while (test_cases--)
solve();
#ifdef DEBUG
cerr << fixed << setprecision(10)
<< "\nTime Taken: " << (double)(clock() - start) / CLOCKS_PER_SEC
<< "s\n";
#endif
return 0;
}
Compilation message
oneway.cpp: In constructor 'ST::ST(int, vii)':
oneway.cpp:132:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
132 | for (int i = 2; i < lg2.size(); i++)
| ~~^~~~~~~~~~~~
oneway.cpp: In function 'int main()':
oneway.cpp:291:11: warning: unused variable 'start' [-Wunused-variable]
291 | clock_t start = clock();
| ^~~~~
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
212 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
212 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
| # |
Verdict |
Execution time |
Memory |
Grader output |
| 1 |
Incorrect |
1 ms |
212 KB |
Output isn't correct |
| 2 |
Halted |
0 ms |
0 KB |
- |
