Submission #579879

#	Time	Username	Problem	Language	Result	Execution time	Memory
579879		dxz05	One-Way Streets (CEOI17_oneway)	C++14	0 / 100	3028 ms	23964 KiB

oneway

#pragma GCC optimize("Ofast,O2,O3,unroll-loops")
#pragma GCC target("avx2")

#include <bits/stdc++.h>

#include <random>

using namespace std;

void debug_out() { cerr << endl; }

template<typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
    cerr << "[" << H << "]";
    debug_out(T...);
}

#ifdef dddxxz
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

#define SZ(s) ((int)s.size())
#define all(x) (x).begin(), (x).end()
#define lla(x) (x).rbegin(), (x).rend()
#define bpc(x) __builtin_popcount(x)
#define bpcll(x) __builtin_popcountll(x)

clock_t startTime;

double getCurrentTime() {
    return (double) (clock() - startTime) / CLOCKS_PER_SEC;
}

#define MP make_pair

typedef long long ll;
mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());
const double eps = 0.000001;
const int MOD = 1e9 + 7;
const int INF = 1000000101;
const long long LLINF = 1223372000000000555;
const int N = 1e6 + 3e2;
const int M = 1111;

int eu[N], ev[N];

vector<int> g[N];

int flag[N];

int blocked_x, blocked_y;

bool used[N];
void dfs(int v){
    used[v] = true;
    for (int u : g[v]){
        if (v == blocked_x && u == blocked_y) continue;
        if (!used[u]) dfs(u);
    }
}

void solve(int TC) {
    int n, m;
    cin >> n >> m;

    map<pair<int, int>, int> mp;
    for (int i = 1; i <= m; i++){
        int x, y;
        cin >> x >> y;

        eu[i] = x, ev[i] = y;

        if (x > y) swap(x, y);
        if (mp.find(MP(x, y)) != mp.end()){
            flag[i] = flag[mp[MP(x, y)]] = 3;
            continue;
        }
        mp[MP(x, y)] = i;

        g[x].push_back(y);
        g[y].push_back(x);
    }

    int q;
    cin >> q;

    vector<pair<int, int>> important;
    while (q--){
        int x, y;
        cin >> x >> y;
        important.emplace_back(x, y);
    }

    for (int i = 1; i <= m; i++){
        if (flag[i] == 3) continue;

        bool left = true, right = true;
        for (auto now : important){
            int x = now.first, y = now.second;

            blocked_x = eu[i];
            blocked_y = ev[i];

            fill(used + 1, used + n + 1, false);
            dfs(x);

            if (!used[y]) left = false;

            blocked_x = ev[i];
            blocked_y = eu[i];

            fill(used + 1, used + n + 1, false);
            dfs(x);

            if (!used[y]) right = false;
        }

        if (left) flag[i] |= 1;
        if (right) flag[i] |= 2;
        assert(flag[i] > 0);
    }

    for (int i = 1; i <= m; i++){
        cout << (flag[i] == 1 ? 'L' : flag[i] == 2 ? 'R' : 'B');
    }

}

int main() {
    startTime = clock();
    ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);

#ifdef dddxxz
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    int TC = 1;
    //    cin >> TC;

    for (int test = 1; test <= TC; test++) {
        //debug(test);
        //cout << "Case #" << test << ": ";
        solve(test);
    }

#ifdef dddxxz
    cerr << endl << "Time: " << int(getCurrentTime() * 1000) << " ms" << endl;
#endif

    return 0;
}

• Subtask 1: 0 / 30
• Subtask 2: 0 / 30
• Subtask 3: 0 / 40