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Submission #697428

# Submission time Handle Problem Language Result Execution time Memory
697428 2023-02-09T18:31:01 Z Arshi One-Way Streets (CEOI17_oneway) C++17
100 / 100
 216 ms 40760 KB 
/**********************GOD**********************/

#include <iostream>
#include <algorithm>
#include <cmath>
#include <iomanip>
#include <cstdlib>
#include <string>
#include <vector>
#include <set>
#include <queue>
#include <stack>
#include <iterator>
#include <map>

using namespace std;

typedef long long ll;
typedef pair<ll , ll> pll;

#define len                 length()
#define MP                  make_pair
#define fs                  first
#define sc                  second
#define pb(x)               push_back(x)
#define all(x)              x.begin() , x.end()
#define kill(x)             cout << x , exit(0)

const ll MAXN = 2e5 + 5;
const ll INF = 1e18 + 8;
const ll LOG = 23;
const ll mod = 1e9 + 7;

ll n , m , q;

vector<pll> adj[MAXN] , E;
ll dp[MAXN][2] , h[MAXN] , be[MAXN] , par[MAXN][LOG] , ans[MAXN];
bool mark[MAXN];

void DFS1(ll v)
{
    for(ll i = 1 ; i < LOG ; i ++)
        par[v][i] = par[par[v][i - 1]][i - 1];

    mark[v] = 1;
    be[v] = h[v];

    for(auto[u , _] : adj[v])
    {
        if(!mark[u])
        {
            par[u][0] = v;
            h[u] = h[v] + 1;

            DFS1(u);

            be[v] = min(be[v] , be[u]);
        }
        else if(h[u] + 1 < h[v])
            be[v] = min(be[v] , h[u]);
        else if(h[u] == h[v] + 1)
            be[u] = min(be[u] , h[u] - 1);
    }
}

void DFS2(ll v , ll id = 0)
{
    mark[v] = 1;

    for(auto[u , i] : adj[v])
        if(!mark[u])
            DFS2(u , i) ,
            dp[v][0] += dp[u][0] , dp[v][1] += dp[u][1];

    ans[id] = (dp[v][0] ? 2 : 3);
    if(be[v] < h[v]) ans[id] = 1;
    if(!dp[v][0] && !dp[v][1]) ans[id] = 1;
}

ll GetPar(ll v , ll k)
{
    for(ll i = 0 ; i < LOG ; i ++){
        if(k >> i & 1)
            v = par[v][i];
    }

    return v;
}

ll LCA(ll v , ll u)
{
    if(h[v] < h[u]) swap(v , u);

    v = GetPar(v , h[v] - h[u]);
    if(v == u) return v;

    for(ll i = LOG - 1 ; i >= 0 ; i --){
        if(par[v][i] != par[u][i]){
            v = par[v][i];
            u = par[u][i];
        }
    }

    return par[v][0];
}

int main()
{
    ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

    cin >> n >> m;

    E.pb(MP(0 , 0));
    for(ll i = 1 ; i <= m ; i ++)
    {
        ll v , u;
        cin >> v >> u;

        E.pb(MP(v , u));
        if(v == u){
            ans[i] = 1;
            continue;
        }

        adj[v].pb(MP(u , i));
        adj[u].pb(MP(v , i));
    }

    for(ll i = 1 ; i <= n ; i ++)
        if(!mark[i])
            DFS1(i);

    cin >> q;
    while(q --)
    {
        ll v , u , w;
        cin >> v >> u;

        w = LCA(v , u);

        dp[v][0] ++;
        dp[u][1] ++;
        dp[w][0] --;
        dp[w][1] --;
    }

    fill(mark , mark + n + 1 , 0);
    for(ll i = 1 ; i <= n ; i ++)
        if(!mark[i])
            DFS2(i);

    for(ll i = 1 ; i <= m ; i ++)
    {
        auto[v , u] = E[i];

        if(ans[i] == 1) { cout << "B"; continue; }
        if((h[v] > h[u] && be[v] < h[v]) || (h[u] > h[v] && be[u] < h[u])) { cout << "B"; continue; }

        if(h[v] > h[u])
        {
            if(ans[i] == 2)
                cout << "R";
            else
                cout << "L";
        }
        else
        {
            if(ans[i] == 2)
                cout << "L";
            else
                cout << "R";
        }
    }

    return 0;
}

/*!
ahkh
*/

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4948 KB Output is correct
2 Correct 3 ms 4948 KB Output is correct
3 Correct 3 ms 5296 KB Output is correct
4 Correct 4 ms 5332 KB Output is correct
5 Correct 3 ms 5292 KB Output is correct
6 Correct 3 ms 5204 KB Output is correct
7 Correct 3 ms 5332 KB Output is correct
8 Correct 3 ms 5332 KB Output is correct
9 Correct 3 ms 5204 KB Output is correct
10 Correct 3 ms 5204 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4948 KB Output is correct
2 Correct 3 ms 4948 KB Output is correct
3 Correct 3 ms 5296 KB Output is correct
4 Correct 4 ms 5332 KB Output is correct
5 Correct 3 ms 5292 KB Output is correct
6 Correct 3 ms 5204 KB Output is correct
7 Correct 3 ms 5332 KB Output is correct
8 Correct 3 ms 5332 KB Output is correct
9 Correct 3 ms 5204 KB Output is correct
10 Correct 3 ms 5204 KB Output is correct
11 Correct 45 ms 18628 KB Output is correct
12 Correct 62 ms 21900 KB Output is correct
13 Correct 90 ms 26700 KB Output is correct
14 Correct 114 ms 33364 KB Output is correct
15 Correct 111 ms 35168 KB Output is correct
16 Correct 100 ms 34996 KB Output is correct
17 Correct 106 ms 36544 KB Output is correct
18 Correct 94 ms 35000 KB Output is correct
19 Correct 103 ms 37748 KB Output is correct
20 Correct 76 ms 25228 KB Output is correct
21 Correct 63 ms 24872 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 4948 KB Output is correct
2 Correct 3 ms 4948 KB Output is correct
3 Correct 3 ms 5296 KB Output is correct
4 Correct 4 ms 5332 KB Output is correct
5 Correct 3 ms 5292 KB Output is correct
6 Correct 3 ms 5204 KB Output is correct
7 Correct 3 ms 5332 KB Output is correct
8 Correct 3 ms 5332 KB Output is correct
9 Correct 3 ms 5204 KB Output is correct
10 Correct 3 ms 5204 KB Output is correct
11 Correct 45 ms 18628 KB Output is correct
12 Correct 62 ms 21900 KB Output is correct
13 Correct 90 ms 26700 KB Output is correct
14 Correct 114 ms 33364 KB Output is correct
15 Correct 111 ms 35168 KB Output is correct
16 Correct 100 ms 34996 KB Output is correct
17 Correct 106 ms 36544 KB Output is correct
18 Correct 94 ms 35000 KB Output is correct
19 Correct 103 ms 37748 KB Output is correct
20 Correct 76 ms 25228 KB Output is correct
21 Correct 63 ms 24872 KB Output is correct
22 Correct 216 ms 37780 KB Output is correct
23 Correct 183 ms 36312 KB Output is correct
24 Correct 149 ms 36064 KB Output is correct
25 Correct 205 ms 40760 KB Output is correct
26 Correct 199 ms 37336 KB Output is correct
27 Correct 165 ms 36244 KB Output is correct
28 Correct 37 ms 12036 KB Output is correct
29 Correct 130 ms 25976 KB Output is correct
30 Correct 148 ms 26052 KB Output is correct
31 Correct 130 ms 26428 KB Output is correct
32 Correct 151 ms 30904 KB Output is correct