oj.uz

Submission #706940

# Submission time Handle Problem Language Result Execution time Memory
706940 2023-03-08T06:56:38 Z mychecksedad One-Way Streets (CEOI17_oneway) C++17
100 / 100
 171 ms 35492 KB 
/* Author : Mychecksdead */
#include<bits/stdc++.h>
using namespace std;
typedef long long int ll;
#define MOD (1000000000+7)
#define MOD1 (998244353)
#define PI 3.1415926535
#define pb push_back
#define all(x) x.begin(), x.end()
const int N = 2e5+100, M = 1e5+10, K = 20;


int n, m, p, tin[N], tout[N], up[N][K], par[N][2], lo[N], timer = 0, ti[N], dp[N];
vector<pair<int, int>> g[N], f[N];
vector<bool> vis, bridge;
string s = "";

void st(int v){
  vis[v] = 1;
  for(auto U: g[v]){
    int u = U.first, idx = U.second;
    if(!vis[u]){
      f[v].pb({u, idx});
      f[u].pb({v, idx^1});
      par[u][0] = v;
      par[u][1] = idx;
      st(u);
    }
  }
}

void pre(int v, int p){
  tin[v] = timer++;
  up[v][0] = p;
  for(auto U: f[v]){
    int u = U.first;
    if(u != p){
      pre(u, v);
    }
  }
  tout[v] = timer++;
}

bool is_ancestor(int u, int v){
  return tin[u] <= tin[v] && tout[v] <= tout[u];
}

int _lca(int u, int v){
  if(is_ancestor(u, v)) return u;
  if(is_ancestor(v, u)) return v;
  for(int j = K - 1; j >= 0 ;--j){
    if(!is_ancestor(up[u][j], v)) u = up[u][j];
  }
  return up[u][0];
}


void bf(int v, int pp){
  ti[v] = lo[v] = timer++;
  vis[v] = 1;
  for(auto U: g[v]){
    int u = U.first, idx = U.second;
    if(idx/2 == pp/2) continue;
    if(vis[u]){
      lo[v] = min(lo[v], ti[u]);
    }else{
      bf(u, idx);
      lo[v] = min(lo[v], lo[u]);
      if(lo[u] > ti[v]){
        bridge[idx>>1] = 1;
      }
    }
  }
}

int dfs(int v, int p){
  int w = 0;
  vis[v] = 1;
  for(auto U: f[v]){
    int u = U.first;
    if(u != p){
      w += dfs(u, v);
    }
  }
  w += dp[v];
  if(p != v){
    if(w < 0){
      int e = par[v][1];
      if(bridge[e>>1]){
        s[e>>1] = ((e&1)^1) ? 'R' : 'L';
      }
    }else if(w > 0){
      int e = par[v][1];
      if(bridge[e>>1]){
        s[e>>1] = (e&1) ? 'R' : 'L';
      }
    }
  }
  return w;
}

void solve(){
  cin >> n >> m;
  for(int i = 0 ; i < m; ++i){
    int u, v; cin >> u >> v;
    g[u].pb({v, i*2});
    g[v].pb({u, i*2+1});
    s += 'B';
  }
  vis.resize(n + 1, 0);
  for(int i = 1; i <= n; ++i) if(!vis[i]) st(i), pre(i, i);
  for(int j = 1; j < K; ++j) for(int i = 1; i <= n; ++i) up[i][j] = up[up[i][j - 1]][j - 1];

  vis.clear();
  vis.resize(n + 1, 0);
  bridge.resize(m, 0);
  timer = 0;
  for(int i = 1; i <= n; ++i) if(!vis[i]) bf(i, MOD);


  cin >> p;
  for(int i = 0; i < p; ++i){
    int u, v; cin >> u >> v;
    dp[u]++;
    dp[v]--;
  }
  vis.clear();
  vis.resize(n, 0);
  for(int i = 1; i <= n; ++i) if(!vis[i]) dfs(i, i);
  cout << s;
}


int main(){
  cin.tie(0); ios::sync_with_stdio(0);
  int T = 1, aa;
  // freopen("in.txt", "r", stdin);
  // cin >> T;aa=T;
  while(T--){
    // cout << "Case #" << aa-T << ": ";
    solve();
  }
  return 0;
 
}

Compilation message

oneway.cpp: In function 'int main()':
oneway.cpp:136:14: warning: unused variable 'aa' [-Wunused-variable]
  136 |   int T = 1, aa;
      |              ^~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 9684 KB Output is correct
2 Correct 5 ms 9684 KB Output is correct
3 Correct 6 ms 9844 KB Output is correct
4 Correct 6 ms 9940 KB Output is correct
5 Correct 5 ms 9940 KB Output is correct
6 Correct 6 ms 9812 KB Output is correct
7 Correct 7 ms 9956 KB Output is correct
8 Correct 7 ms 9864 KB Output is correct
9 Correct 5 ms 9868 KB Output is correct
10 Correct 5 ms 9812 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 9684 KB Output is correct
2 Correct 5 ms 9684 KB Output is correct
3 Correct 6 ms 9844 KB Output is correct
4 Correct 6 ms 9940 KB Output is correct
5 Correct 5 ms 9940 KB Output is correct
6 Correct 6 ms 9812 KB Output is correct
7 Correct 7 ms 9956 KB Output is correct
8 Correct 7 ms 9864 KB Output is correct
9 Correct 5 ms 9868 KB Output is correct
10 Correct 5 ms 9812 KB Output is correct
11 Correct 42 ms 17388 KB Output is correct
12 Correct 57 ms 19928 KB Output is correct
13 Correct 67 ms 23584 KB Output is correct
14 Correct 85 ms 28156 KB Output is correct
15 Correct 98 ms 29360 KB Output is correct
16 Correct 99 ms 28780 KB Output is correct
17 Correct 91 ms 30924 KB Output is correct
18 Correct 88 ms 29132 KB Output is correct
19 Correct 93 ms 32040 KB Output is correct
20 Correct 65 ms 22348 KB Output is correct
21 Correct 52 ms 22092 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 9684 KB Output is correct
2 Correct 5 ms 9684 KB Output is correct
3 Correct 6 ms 9844 KB Output is correct
4 Correct 6 ms 9940 KB Output is correct
5 Correct 5 ms 9940 KB Output is correct
6 Correct 6 ms 9812 KB Output is correct
7 Correct 7 ms 9956 KB Output is correct
8 Correct 7 ms 9864 KB Output is correct
9 Correct 5 ms 9868 KB Output is correct
10 Correct 5 ms 9812 KB Output is correct
11 Correct 42 ms 17388 KB Output is correct
12 Correct 57 ms 19928 KB Output is correct
13 Correct 67 ms 23584 KB Output is correct
14 Correct 85 ms 28156 KB Output is correct
15 Correct 98 ms 29360 KB Output is correct
16 Correct 99 ms 28780 KB Output is correct
17 Correct 91 ms 30924 KB Output is correct
18 Correct 88 ms 29132 KB Output is correct
19 Correct 93 ms 32040 KB Output is correct
20 Correct 65 ms 22348 KB Output is correct
21 Correct 52 ms 22092 KB Output is correct
22 Correct 102 ms 31876 KB Output is correct
23 Correct 106 ms 30040 KB Output is correct
24 Correct 171 ms 30296 KB Output is correct
25 Correct 101 ms 35492 KB Output is correct
26 Correct 99 ms 31524 KB Output is correct
27 Correct 111 ms 30164 KB Output is correct
28 Correct 33 ms 13260 KB Output is correct
29 Correct 73 ms 23092 KB Output is correct
30 Correct 68 ms 23168 KB Output is correct
31 Correct 82 ms 23564 KB Output is correct
32 Correct 75 ms 27532 KB Output is correct