제출 #468125

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
468125		Vladth11	One-Way Streets (CEOI17_oneway)	C++14	100 / 100	235 ms	26552 KiB

oneway

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define debug(x) cerr << #x << " " << x << "\n"
#define debugs(x) cerr << #x << " " << x << " "
#pragma GCC optimize("Ofast,unroll-loops")

using namespace std;
using namespace __gnu_pbds;
typedef long long ll;
typedef pair <int, int> pii;
typedef pair <long double, pii> muchie;
typedef tree <ll, null_type, less_equal <ll>, rb_tree_tag, tree_order_statistics_node_update> OST;

const ll NMAX = 100001;
const ll INF = (1LL << 60);
const ll HALF = (1LL << 59);
const ll MOD = 30013;
const ll BLOCK = 318;
const ll base = 31;
const ll nr_of_bits = 21;

int n, m;
int lvl[NMAX];
int dp[NMAX];
int viz[NMAX];
int cnt;
int dest[NMAX];
int sursa[NMAX];
int surse[NMAX];
int deste[NMAX];
int comp[NMAX];
int parent[NMAX];
int bl[NMAX][nr_of_bits + 1];
vector <int> v[NMAX];
int stamp;
pii timp[NMAX];

bool par(int a, int b){
    return timp[a].first <= timp[b].first && timp[b].second <= timp[a].second;
}

void DFS(int node, int p){
    lvl[node] = lvl[p] + 1;
    parent[node] = p;
    for(auto x : v[node]){
        if(!lvl[x]){
            DFS(x, node);
            dp[node] += dp[x];
        }else if(lvl[x] > lvl[node]){
            dp[node]--;
        }else{
            dp[node]++;
        }
    }
    if(lvl[node] != 1)
        dp[node]--;
}

void assignComp(int node, int p){
    if(!dp[node]){
        cnt++;
        timp[cnt].first = ++stamp;
        comp[node] = cnt;
        if(comp[p] != 0){
            bl[comp[node]][0] = comp[p];
        }
    }else{
        comp[node] = comp[p]; ///nu cnttt ca se modifica
    }
    for(auto x : v[node]){
        if(!comp[x]){
            assignComp(x, node);
        }
    }
    timp[comp[node]].second = stamp;
}

pii special[NMAX];
pii edges[NMAX];

void calc(int node, int p){
    viz[node] = 1;
    for(auto x : v[node]){
        if(!viz[x]){
            calc(x, node);
            if(comp[node] != comp[x]){
                surse[comp[node]] += surse[comp[x]];
                deste[comp[node]] += deste[comp[x]];
            }
        }
    }
}

int lca(int a, int b){
    int r = a;
    int pas = nr_of_bits;
    while(pas >= 0){
        int nxt = bl[r][pas];
        if(nxt != 0 && !par(nxt, b))
            r = nxt;
        pas--;
    }
    if(!par(r, b))
        r = bl[r][0];
    return r;
}

int main() {
    int i;
    /// Poate sunt mai multe componente
    cin >> n >> m;
    for(i = 1; i <= m; i++){
        int x, y;
        cin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
        edges[i] = {x, y};
    }
    for(i = 1; i <= n; i++)
        if(!lvl[i])
            DFS(i, 0);
    for(i = 1; i <= n; i++)
        if(!comp[i])
            assignComp(i, 0);
    for(int j = 1; j <= nr_of_bits; j++){
        for(int i = 1; i <= n; i++){
            bl[i][j] = bl[bl[i][j - 1]][j - 1];
        }
    }
    int q;
    cin >> q;
    for(i = 1; i <= q; i++){
        int x, y;
        cin >> x >> y;
        special[i] = {x, y};
        if(comp[x] == comp[y])
            continue;
        if(par(comp[x], comp[y])){
            deste[comp[y]]++;
            ///se termina de adunat la
            deste[comp[x]]--;
            continue;
        }
        if(par(comp[y], comp[x])){
            surse[comp[x]]++;
            ///se termina de adunat la
            surse[comp[y]]--;
            continue;
        }
        surse[comp[x]]++;
        deste[comp[y]]++;
        deste[lca(comp[x], comp[y])]--;
        surse[lca(comp[x], comp[y])]--;
    }
    for(i = 1; i <= n; i++){
        if(!viz[i])
            calc(i, 0);
    }
    for(i = 1; i <= m; i++){
        int x = edges[i].first;
        int y = edges[i].second;
        if(lvl[x] > lvl[y]){
            swap(x, y);
        }
        if(parent[y] != x){
            cout << "B";
            continue;
        }
        if(dp[y] != 0){
            cout << "B";
            continue;
        }
        if(!deste[comp[y]] && !surse[comp[y]]){
            cout << "B";
            continue;
        }
        if(surse[comp[y]] > 0){
            if(y == edges[i].first){
                cout << "R";
            }else{
                cout << "L";
            }
            continue;
        }
        if(y == edges[i].first){
            cout << "L";
        }else{
            cout << "R";
        }
    }
    return 0;
}

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