Submission #995011

#	Time	Username	Problem	Language	Result	Execution time	Memory
995011		NoLove	One-Way Streets (CEOI17_oneway)	C++14	100 / 100	46 ms	21256 KiB

oneway

/**
 *    author : Lăng Trọng Đạt
 *    created: 08-06-2024 
**/
#include <bits/stdc++.h>
using namespace std;
#ifndef LANG_DAT
#define db(...) ;
#endif // LANG_DAT
#define int long long
#define mp make_pair
#define f first
#define se second
#define pb push_back
#define all(v) (v).begin(), (v).end()
using pii = pair<int, int>;
using vi = vector<int>;
#define FOR(i, a, b) for (int (i) = a; (i) <= (b); i++)
void mx(int& a, int b) { if (b > a) a = b; }
void mi(int& a, int b) { if (b < a) a = b; }
#define si(x) (int)(x.size())
const int INF = 1e18;
const int MOD = 1e9 + 7;

const int MAXN = 1e5 + 5;
vector<pii> adj[MAXN];
vector<pii> edges;
int n, m, a, b, p;
int res[MAXN]; // 0 is b, 1 is r, 2 is l
int cnt[MAXN], low[MAXN], id[MAXN], d[MAXN];
int timer = 1;
void dfs(int v, int prv) {
    db(v, prv)
    low[v] = id[v] = timer++;
    bool multi_edge = false;
    for (auto[u, i] : adj[v]) {
        if (u == prv && !multi_edge) {
            multi_edge = true;
            continue;
        }
        if (id[u]) mi(low[v], id[u]);
        else {
            d[u] = d[v] + 1;
            dfs(u, v);
            cnt[v] += cnt[u];
            mi(low[v], low[u]);
            if (id[v] < low[u]) {
                if (cnt[u] == 0) continue;
                db(u, v, cnt[u], edges[i])

                if (cnt[u] > 0) { // u -> v
                    res[i] = (v == edges[i].f ? 2 : 1);
                } else { // v -> u
                    res[i] = (v == edges[i].se ? 2 : 1);
                }
            }
        }
    }
}
int32_t main() {
    cin.tie(0)->sync_with_stdio(0);
    if (fopen("hi.inp", "r")) {
        freopen("hi.inp", "r", stdin);
//        freopen("hi.out", "w", stdout);
    } 

    cin >> n >> m;
    FOR(i, 0, m - 1) {
        cin >> a >> b;
        edges.pb({a, b});
        adj[a].pb({b, i});
        adj[b].pb({a, i});
    }
    cin >> p;
    FOR(i, 1, p) {
        cin >> a >> b;
        cnt[a]++;
        cnt[b]--;
    }
    FOR(i, 1, n) {
        if (!id[i]) {
            dfs(i, -1);
        }
    }
    db(n, m, p)
    FOR(i, 0, m - 1) {
        if (res[i] == 0) cout << 'B';
        else cout << (res[i] == 1 ? 'R' : 'L');
    }
}

Compilation message (stderr)

oneway.cpp: In function 'void dfs(long long int, long long int)':
oneway.cpp:36:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   36 |     for (auto[u, i] : adj[v]) {
      |              ^
oneway.cpp: In function 'int32_t main()':
oneway.cpp:18:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   18 | #define FOR(i, a, b) for (int (i) = a; (i) <= (b); i++)
      |                               ^
oneway.cpp:68:5: note: in expansion of macro 'FOR'
   68 |     FOR(i, 0, m - 1) {
      |     ^~~
oneway.cpp:18:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   18 | #define FOR(i, a, b) for (int (i) = a; (i) <= (b); i++)
      |                               ^
oneway.cpp:75:5: note: in expansion of macro 'FOR'
   75 |     FOR(i, 1, p) {
      |     ^~~
oneway.cpp:18:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   18 | #define FOR(i, a, b) for (int (i) = a; (i) <= (b); i++)
      |                               ^
oneway.cpp:80:5: note: in expansion of macro 'FOR'
   80 |     FOR(i, 1, n) {
      |     ^~~
oneway.cpp:18:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   18 | #define FOR(i, a, b) for (int (i) = a; (i) <= (b); i++)
      |                               ^
oneway.cpp:86:5: note: in expansion of macro 'FOR'
   86 |     FOR(i, 0, m - 1) {
      |     ^~~
oneway.cpp:63:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |         freopen("hi.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 30 / 30
• Subtask 2: 30 / 30
• Subtask 3: 40 / 40