Submission #379803

#	Time	Username	Problem	Language	Result	Execution time	Memory
379803		MladenP	One-Way Streets (CEOI17_oneway)	C++17	100 / 100	90 ms	14188 KiB

oneway

#include <bits/stdc++.h>
#define pii pair<int, int>
#define fi first
#define se second
#define pb push_back
#define PRINT(x) cerr<<#x<<'='<<x<<endl;
#define MAXN 100010
using namespace std;
int N, M, P, w[MAXN], fup[MAXN], dub[MAXN];
vector<pii> adj[MAXN];
pii edge[MAXN];
string s = "#";
void dfs(int node, int e) {
    dub[node] = dub[node^edge[e].fi^edge[e].se]+1;
    fup[node] = dub[node];
    for(auto x : adj[node]) {
        if(x.se == e) continue;
        if(dub[x.fi]) {
            fup[node] = min(fup[node], dub[x.fi]);
        } else {
            dfs(x.fi, x.se);
            w[node] += w[x.fi];
            fup[node] = min(fup[node], fup[x.fi]);
        }
    }
    if(fup[node] != dub[node]) return;
    if(w[node] > 0) {
        int node1 = node^edge[e].fi^edge[e].se;
        if(make_pair(node1, node) == edge[e]) s[e] = 'L';
        else s[e] = 'R';
    } else if(w[node] < 0) {
        int node1 = node^edge[e].fi^edge[e].se;
        if(make_pair(node1, node) == edge[e]) s[e] = 'R';
        else s[e] = 'L';
    }
}
int main() {
    ios::sync_with_stdio(false); cin.tie(0);
    cin >> N >> M;
    for(int i = 1; i <= M; i++) {
        int A, B; cin >> A >> B;
        edge[i] = {A, B};
        adj[A].pb({B, i});
        adj[B].pb({A, i});
        s += "B";
    }
    edge[0] = {1, 0};
    cin >> P;
    for(int i = 1; i <= P; i++) {
        int X, Y; cin >> X >> Y;
        w[X]++; w[Y]--;
    }
    for(int i = 1; i <= N; i++) {
        if(!dub[i]) {
            edge[0] = {i, 0};
            dfs(i, 0);
        }
    }
    for(int i = 1; i <= M; i++) cout << s[i];
    return 0;
}

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