Submission #347776

#	Time	Username	Problem	Language	Result	Execution time	Memory
347776		soroush	One-Way Streets (CEOI17_oneway)	C++14	100 / 100	205 ms	83180 KiB

oneway

/*
#pragma GCC optimize("O2")
#pragma GCC optimize("Ofast")
#pragma GCC optimize("unroll-loops")
#pragma GCC target("avx,avx2,sse,sse2,fma")
//*/
#include <bits/stdc++.h>
 
using namespace std;
 
typedef long long ll;
typedef long double ld;
typedef pair<int , int> pii;
 
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
 
const ll maxn = 3e6;
const ll mod = 1e9+7;
const ld PI = acos((ld)-1);
 
#define pb push_back
#define endl '\n'
#define dokme(x) cout << x , exit(0)
#define migmig ios::sync_with_stdio(false),cin.tie(0),cout.tie(0)
#define ms(x , y) memset(x , y , sizeof x)
ll pw(ll a, ll b, ll md = mod){ll res = 1;while(b){if(b&1){res=(a*res)%md;}a=(a*a)%md;b>>=1;}return(res);}
 
#define For(i,a,b) for(int i=a;i<=b;i++)
#define fi first
#define se second
int n,m,u,v,t,a[maxn],b[maxn],ans[maxn],dx[maxn];
vector<pair<int,int> >ke[maxn];
void dfs(int u,int x)
{
    dx[u]=1;
    for(auto p:ke[u])
    {
        int v=p.fi;
        int y=p.se;
        if(y!=-x)
        {
            if(!dx[v])
            {
                dfs(v,y);
                a[u]+=a[v];
                b[u]+=b[v];
            }
            else
                if(dx[v]==1)
                {
                    ans[abs(y)]=2;
                    b[u]++;
                    b[v]--;
                }
        }
    }
    if(b[u]>0||a[u]==0) ans[abs(x)]=2;
    else
    {
        int v=a[u];
        if(x<0)
        {
            x=-x;
            v=-v;
        }
        if(v>0) ans[x]=1;
        else ans[x]=3;
    }
    dx[u]=2;
}
int main()
{
    cin >> n >> m;
    For(i,1,m)
    {
        cin >> u >> v;
        ke[u].push_back({v,i});
        ke[v].push_back({u,-i});

    }
    cin >> t;
    For(i,1,t)
    {
        cin >> u >> v;
        a[u]++;
        a[v]--;
    }
    For(i,1,n)
        if(!dx[i])
            dfs(i,0);
    For(i,1,m)
    {
        if(ans[i]==1) cout<<'L';
        if(ans[i]==2) cout<<'B';
        if(ans[i]==3) cout<<'R';
    }
}

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