Submission #709743

#	Time	Username	Problem	Language	Result	Execution time	Memory
709743		ktkerem	One-Way Streets (CEOI17_oneway)	C++17	0 / 100	3 ms	4948 KiB

oneway

/*#pragma GCC target ("avx2")
#pragma GCC optimize ("O3")
#pragma GCC optimize("Ofast")
#pragma GCC optimize ("unroll-loops")
#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")/**/
#include<bits/stdc++.h>
typedef long long ll;
typedef long double ld;
#define llll std::pair<ll , ll>
#define pb push_back
#define fi first
#define sec second
#define all(a) a.begin() , a.end()
#define debug std::cout << "!!ALERT ALERT!!" << std::endl;
const ll limit = 1e18+7;
const ll sus = 1e5 + 5;
std::mt19937 rng(std::chrono::steady_clock::now().time_since_epoch().count());
ll rnd(ll a , ll b){
    return (rng() % (b-a+1)) + a;
}
/*global variables*/
ll n , m , p;
std::vector<ll> adj[sus];std::vector<llll> nadj[sus];
std::vector<std::pair<llll , ll>> eg;
ll vis[sus] , sz[sus] , par[sus];
ll deg[sus] , sdeg[sus] , ans[sus];
/**/
/*functions*/
ll fin(ll x){
    if(par[x] == x){
        return x;
    }
    return par[x] = fin(par[x]);
}
void mrg(ll x , ll y){
    x = fin(x);y = fin(y);
    if(x == y){
        return;
    }
    if(sz[x] < sz[y]){
        std::swap(x , y);
    }
    sz[x] += sz[y];
    par[y] = x; 
}
ll cycdfs(ll crt , ll prv){
    vis[crt] = 1;
    ll o = 0;
    ll p = 0;
    for(auto j:adj[crt]){
        if(p == 0 && j == prv){
            p = 1;
            continue;
        }
        if(vis[j] == 0){
            o += cycdfs(j , crt);
        }
        else if(vis[j] == 1){
            o+=1;
            deg[j]--;
        }
    }
    o+=deg[crt];
    //std::cout << crt << " " << prv << " " << o << "\n";
    if(o > 0){
        //debug;
        mrg(crt , prv);
    }
    vis[crt] = 2; 
    return o;
}
ll sdfs(ll crt , ll prv , ll o){
    ll sm = 0;
    //std::cout << crt << " " << prv << " " << o << std::endl;
    for(auto j:nadj[crt]){
        if(j.fi == prv){
            continue;
        }
        sm += sdfs(j.fi , crt , j.sec);
    }
    sm+=sdeg[crt];
    if(o != -1){
        if((eg[o].fi.fi == prv && sm > 0) || (eg[0].fi.fi != prv && sm < 0)){
            ans[o] = 1;
        }
        else if(sm != 0){
            ans[o] = -1;
        }
    }
    return sm;
}
/**/
void solve(){
    std::cin >> n >> m;
    for(ll i = 0;n>=i;i++){
        par[i] = i;
        sz[i] = 1;
    }
    for(ll i=0;m>i;i++){
        ll x , y;std::cin >> x >> y;
        adj[x].pb(y);
        adj[y].pb(x);
        eg.pb({{x , y} , i});
    }
    for(ll i = 1;n>=i;i++){
        if(vis[i] == 0){
            cycdfs(i , 0);
        }
    }
    for(ll i = 0;m>i;i++){
        if(fin(eg[i].fi.fi) != fin(eg[i].fi.sec)){
            //std::cout << fin(eg[i].fi.fi) << " " << fin(eg[i].fi.sec) << "\n";
            nadj[fin(eg[i].fi.fi)].pb({fin(eg[i].fi.sec) , i});
            nadj[fin(eg[i].fi.sec)].pb({fin(eg[i].fi.fi) , i});
        }
    }
    std::cin >> p;
    while(p--){
        ll x , y;std::cin >> x >> y;
        sdeg[fin(x)]++;
        sdeg[fin(y)]--;
    }
    //std::cout << std::endl;
    sdfs(fin(3) , 0 , -1);
    for(ll i = 0;m>i;i++){
        if(ans[i] > 0){
            std::cout << "L";
        }
        else if(ans[i] < 0){
            std::cout << "R";
        }
        else{
            std::cout << "B";
        }
    }
    return;/**/
}
int main(){
    std::ios_base::sync_with_stdio(false);std::cin.tie(NULL);
    /*#ifndef ONLINE_JUDGE
        freopen("in.txt" , "r" , stdin);
        freopen("out.txt" , "w" , stdout);
    #endif*/
    ll t = 1;
    //std::cin >> t;
    while(t--){
        solve();
    }
}

Compilation message (stderr)

oneway.cpp:5:78: warning: "/*" within comment [-Wcomment]
    5 | #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")/**/
      |

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