제출 #98002

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
98002		popovicirobert	One-Way Streets (CEOI17_oneway)	C++14	100 / 100	207 ms	22848 KiB

oneway

#include <bits/stdc++.h>
#define lsb(x) (x & (-x))
#define ll long long
#define ull unsigned long long
#define ld long double
// 217
// 44

using namespace std;

const int MAXN = (int) 1e5;

vector < pair <int, int> > g[MAXN + 1];
int lvl[MAXN + 1], low[MAXN + 1];
int id[MAXN + 1], cnt;
stack <int> stk;

char sol[MAXN + 1];

void dfs(int nod, int par) {
    lvl[nod] = lvl[par] + 1;
    low[nod] = lvl[nod];
    stk.push(nod);
    bool ok = 0;
    for(auto it : g[nod]) {
        if(lvl[it.first] == 0) {
            dfs(it.first, nod);
            low[nod] = min(low[nod], low[it.first]);
            if(low[it.first] > lvl[nod]) {
                cnt++;
                while(stk.size() && stk.top() != it.first) {
                    id[stk.top()] = cnt;
                    stk.pop();
                }
                id[stk.top()] = cnt;
                stk.pop();
                sol[it.second] = 0;
            }
        }
        else {
            if(it.first != par) {
                low[nod] = min(low[nod], lvl[it.first]);
            }
            else {
                if(ok == 1) {
                    low[nod] = min(low[nod], lvl[it.first]);
                }
                ok = 1;
            }
        }
    }
}

vector < pair <int, int> > tree[MAXN + 1];
pair <int, int> edges[MAXN + 1];
bool vis[MAXN + 1];
int sp[MAXN + 1];

void dfs1(int nod, int par) {
    vis[nod] = 1;
    for(auto it : tree[nod]) {
        if(vis[it.first] == 0) {
            dfs1(it.first, nod);
            sp[nod] += sp[it.first];
            if(sp[it.first] > 0) {
                if(id[edges[it.second].first] == it.first) {
                    sol[it.second] = 'R';
                }
                else {
                    sol[it.second] = 'L';
                }
            }
            else if(sp[it.first] < 0) {
                if(id[edges[it.second].first] == it.first) {
                    sol[it.second] = 'L';
                }
                else {
                    sol[it.second] = 'R';
                }
            }
            else {
                sol[it.second] = 'B';
            }
        }
    }
}

int main() {
    //ifstream cin("A.in");
    //ofstream cout("A.out");
    int i, n, m, q;
    ios::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);
    cin >> n >> m;
    for(i = 1; i <= m; i++) {
        int x, y;
        cin >> x >> y;
        edges[i] = {x, y};
        g[x].push_back({y, i});
        g[y].push_back({x, i});
    }
    memset(sol, 'B', sizeof(sol));
    for(i = 1; i <= n; i++) {
        if(lvl[i] == 0) {
            dfs(i, 0);
        }
    }
    cnt++;
    while(stk.size()) {
        id[stk.top()] = cnt;
        stk.pop();
    }
    for(i = 1; i <= n; i++) {
        for(auto it : g[i]) {
            if(id[i] != id[it.first]) {
                tree[id[i]].push_back({id[it.first], it.second});
            }
        }
    }
    cin >> q;
    for(i = 1; i <= q; i++) {
        int x, y;
        cin >> x >> y;
        sp[id[x]]++;
        sp[id[y]]--;
    }
    for(i = 1; i <= cnt; i++) {
        if(vis[i] == 0) {
            dfs1(i, 0);
        }
    }
    for(i = 1; i <= m; i++) {
        cout << sol[i];
    }
    //cin.close();
    //cout.close();
    return 0;
}

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