oj.uz

Submission #1118838

# Submission time Handle Problem Language Result Execution time Memory
1118838 2024-11-26T08:30:49 Z gdragon One-Way Streets (CEOI17_oneway) C++17
100 / 100
 107 ms 24384 KB 
#include <bits/stdc++.h>
using namespace std;
#define TASK "long"
#define fi first
#define se second
#define ll long long
#define pb push_back
#define ALL(x) (x).begin(), (x).end()
#define GETBIT(mask, i) ((mask) >> (i) & 1)
#define MASK(i) ((1LL) << (i))
#define SZ(x) ((int)(x).size())
#define mp make_pair
#define CNTBIT(mask) __builtin_popcount(mask)
template<class X, class Y> bool maximize(X &x, Y y){ if (x < y) {x = y; return true;} return false;};
template<class X, class Y> bool minimize(X &x, Y y){ if (x > y) {x = y; return true;} return false;};
typedef pair<int, int> ii;
const int N = 1e5 + 5;
const int inf = 1e9 + 7;
const long long INF = (long long)1e18 + 7;
const int mod = 1e9 + 7;
struct Edge {
    int u, v;
    bool isBridge, used;
    Edge(int _u = 0, int _v = 0) {
        u = _u; v = _v;
        isBridge = used = 0;
    }
} e[N];
int n, m, q;
int low[N], num[N];
vector<int> adj[N];
vector<ii> newAdj[N];
void read() {
    cin >> n >> m;
    for(int i = 1; i <= m; i++) {
        int u, v; cin >> u >> v;
        e[i] = Edge(u, v);
        adj[u].push_back(i);
        adj[v].push_back(i);
    }
}
int timer = 0, cycle = 0;
stack<int> st;
int id[N];
void tarjan(int u) {
    low[u] = num[u] = ++timer;
    st.push(u);
    for(int i: adj[u]) if (!e[i].used) {
        e[i].used = 1;
        int v = e[i].u ^ e[i].v ^ u;
        if (num[v]) low[u] = min(low[u], num[v]);
        else {
            tarjan(v);
            low[u] = min(low[u], low[v]);
        }
        if (low[v] > num[u]) {
            // cerr << "BRIDGE: " << e[i].u << ' ' << e[i].v << endl;
            e[i].isBridge = 1;
        }
    }
    if (low[u] == num[u]) {
        ++cycle;
        // cerr << cycle << endl;
        while(true) {
            int v = st.top(); st.pop();
            // cerr << v << ' ';
            low[v] = num[v] = inf;
            id[v] = cycle;
            if (v == u) break;
        }
        // cerr << endl;
    }
}
int tin[N], tout[N], high[N];
ii par[N];
bool isChild(int u, int p) {
    return tin[u] >= tin[p] && tin[u] <= tout[p];
}
int jump[N];
void dfs(int u, int p) {
    // cerr << u << endl;
    tin[u] = ++timer;
    jump[u] = u;
    for(auto [v, i]: newAdj[u]) if (v != p) {
        par[v] = {u, i};
        high[v] = high[u] + 1;
        dfs(v, u);
    } 
    tout[u] = timer;
}
int ans[N];
int change[N];
vector<int> node;
void solve() {
    for(int i = 1; i <= n; i++) if (!num[i]) {
        tarjan(i);
        // assert(i == 1);
    }
    for(int i = 1; i <= m; i++) if (e[i].isBridge) {
        int u = id[e[i].u], v = id[e[i].v];
        newAdj[u].push_back({v, i});
        newAdj[v].push_back({u, i});
    }
    timer = 0;
    for(int i = 1; i <= cycle; i++) if (!tin[i]) dfs(i, -1);
    cin >> q;
    while(q--) {
        int u, v; cin >> u >> v;
        // cerr << id[u] << ' ' << id[v] << endl;
        if (id[u] == id[v]) continue;
        u = id[u]; v = id[v];
        int tmp = u;
        // cerr << jump[u] << ' ' << v << ' ' << isChild(jump[u], v) << endl;
        while(!isChild(v, jump[u])) {
            int i = par[jump[u]].se;
            // u = par[u].fi;
            ans[i] = 1;
            node.push_back(u);
            u = par[jump[u]].fi;
        }
        for(int x: node) jump[x] = u;
        node.clear();
        u = tmp;
        while(!isChild(u, jump[v])) {
            int i = par[jump[v]].se;
            ans[i] = 2;
            // cerr << v << ' ' << e[i].u << ' ' << e[i].v << endl;
            node.push_back(v);
            v = par[jump[v]].fi;
        }
        for(int x: node) jump[x] = v;
        node.clear();
    }
    for(int i = 1; i <= m; i++) {
        // cout << e[i].u << ' ' << e[i].v << ' ';
        if (e[i].isBridge) {
            if (ans[i] != 0) {
                int u = e[i].u, v = e[i].v;
                if (high[id[u]] < high[id[v]]) {
                    assert(isChild(id[v], id[u]));
                    if (ans[i] == 2) cout << 'R';
                    else cout << 'L';
                }
                else {
                    assert(isChild(id[u], id[v]));
                    if (ans[i] == 2) cout << 'L';
                    else cout << 'R';
                }
            }
            else cout << 'B';
            // cout << endl;
            continue;
        }
        else cout << 'B';
        // cout << endl;
    }
}
signed main() {
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    if (fopen(TASK".inp", "r")) {
        freopen(TASK".inp", "r", stdin);
        freopen(TASK".out", "w", stdout);
    }
    int test = 1;
    // cin >> test;
    while(test--) {
        read();
        solve();
    }
    return 0;
}

// rmq - rmq2d
// hash
// fw - fw2d
// segtree

Compilation message

oneway.cpp: In function 'int main()':
oneway.cpp:161:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  161 |         freopen(TASK".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
oneway.cpp:162:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  162 |         freopen(TASK".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 6224 KB Output is correct
2 Correct 5 ms 6236 KB Output is correct
3 Correct 7 ms 6236 KB Output is correct
4 Correct 6 ms 6488 KB Output is correct
5 Correct 6 ms 6492 KB Output is correct
6 Correct 7 ms 6236 KB Output is correct
7 Correct 6 ms 6492 KB Output is correct
8 Correct 5 ms 6480 KB Output is correct
9 Correct 6 ms 6248 KB Output is correct
10 Correct 5 ms 6224 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 6224 KB Output is correct
2 Correct 5 ms 6236 KB Output is correct
3 Correct 7 ms 6236 KB Output is correct
4 Correct 6 ms 6488 KB Output is correct
5 Correct 6 ms 6492 KB Output is correct
6 Correct 7 ms 6236 KB Output is correct
7 Correct 6 ms 6492 KB Output is correct
8 Correct 5 ms 6480 KB Output is correct
9 Correct 6 ms 6248 KB Output is correct
10 Correct 5 ms 6224 KB Output is correct
11 Correct 37 ms 9396 KB Output is correct
12 Correct 39 ms 10312 KB Output is correct
13 Correct 38 ms 11684 KB Output is correct
14 Correct 50 ms 13640 KB Output is correct
15 Correct 48 ms 14376 KB Output is correct
16 Correct 63 ms 18076 KB Output is correct
17 Correct 61 ms 19016 KB Output is correct
18 Correct 65 ms 17312 KB Output is correct
19 Correct 55 ms 19880 KB Output is correct
20 Correct 34 ms 11212 KB Output is correct
21 Correct 37 ms 10312 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 6224 KB Output is correct
2 Correct 5 ms 6236 KB Output is correct
3 Correct 7 ms 6236 KB Output is correct
4 Correct 6 ms 6488 KB Output is correct
5 Correct 6 ms 6492 KB Output is correct
6 Correct 7 ms 6236 KB Output is correct
7 Correct 6 ms 6492 KB Output is correct
8 Correct 5 ms 6480 KB Output is correct
9 Correct 6 ms 6248 KB Output is correct
10 Correct 5 ms 6224 KB Output is correct
11 Correct 37 ms 9396 KB Output is correct
12 Correct 39 ms 10312 KB Output is correct
13 Correct 38 ms 11684 KB Output is correct
14 Correct 50 ms 13640 KB Output is correct
15 Correct 48 ms 14376 KB Output is correct
16 Correct 63 ms 18076 KB Output is correct
17 Correct 61 ms 19016 KB Output is correct
18 Correct 65 ms 17312 KB Output is correct
19 Correct 55 ms 19880 KB Output is correct
20 Correct 34 ms 11212 KB Output is correct
21 Correct 37 ms 10312 KB Output is correct
22 Correct 68 ms 19016 KB Output is correct
23 Correct 107 ms 19316 KB Output is correct
24 Correct 89 ms 19584 KB Output is correct
25 Correct 83 ms 24384 KB Output is correct
26 Correct 86 ms 20608 KB Output is correct
27 Correct 99 ms 19368 KB Output is correct
28 Correct 35 ms 8616 KB Output is correct
29 Correct 65 ms 12272 KB Output is correct
30 Correct 62 ms 12620 KB Output is correct
31 Correct 54 ms 12716 KB Output is correct
32 Correct 89 ms 16728 KB Output is correct