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Submission #521412

# Submission time Handle Problem Language Result Execution time Memory
521412 2022-02-02T05:35:03 Z Wayne_Yan One-Way Streets (CEOI17_oneway) C++17
100 / 100
 152 ms 29256 KB 
#include <bits/extc++.h>
using namespace std;
using namespace __gnu_pbds;

typedef int64_t ll;
typedef long double ld;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define pb emplace_back
#define mp make_pair
#define mt make_tuple
#define pii pair<int,int>
#define F(n) Fi(i,n)
#define Fi(i,n) Fl(i,0,n)
#define Fl(i,l,n) for(int i=l;i<n;i++)
#define RF(n) RFi(i,n)
#define RFi(i,n) RFl(i,0,n)
#define RFl(i,l,n) for(int i=n-1;i>=l;i--)
#define all(v) begin(v),end(v)
#define siz(v) (ll(v.size()))
#define get_pos(v,x) (lower_bound(all(v),x)-begin(v))
#define sort_uni(v) sort(begin(v),end(v)),v.erase(unique(begin(v),end(v)),end(v))
#define mem(v,x) memset(v,x,sizeof v)
#define ff first
#define ss second
#define mid ((l+r)>>1)
#define RAN(a,b) uniform_int_distribution<int> (a, b)(rng)
#define debug(x) (cerr << (#x) << " = " << x << "\n")
#define cmax(a,b) (a = max(a,b))
#define cmin(a,b) (a = min(a,b))

template <typename T> using max_heap = __gnu_pbds::priority_queue<T,less<T> >;
template <typename T> using min_heap = __gnu_pbds::priority_queue<T,greater<T> >;
template <typename T> using rbt = tree<T,null_type,less<T>,rb_tree_tag,tree_order_statistics_node_update>;

const int maxN = 1e5+10;
vector<int> edge[maxN];
int depth[maxN];
int low[maxN];
bool visited[maxN];
stack<int> st;
int bcc[maxN];

vector<int> t_edge[maxN];

void tarjan(int c, int p){
  depth[c] = (p ? depth[p] + 1 : 0);
  low[c] = depth[c];
  visited[c] = true;
  st.push(c);
  
  int cnt_fa = 0;
  for(int i : edge[c]){
    if(i == p && !cnt_fa){
      cnt_fa = 1;
      continue;
    }
    if(visited[i]){
      cmin(low[c], depth[i]);
    }else{
      tarjan(i, c);
      cmin(low[c], low[i]);
    }
  }
  
  if(low[c] == depth[c]){
    int tmp = st.top();
    do{
      tmp = st.top();
      bcc[tmp] = c;
      st.pop();
    }while(tmp != c);
  }
}

int ST[18][maxN];
int fa[maxN];

pii tab[maxN];
char ans[maxN];

int dsu[2][maxN]; // 0 down, 1 up.

int query(int i, int a){
  return dsu[i][a] == a ? a : dsu[i][a] = query(i, dsu[i][a]);
}

void merge(int i, int a, int b){
  if(query(i, a) != query(i, b)) dsu[i][query(i, a)] = query(i, b);
}

int t_depth[maxN];
bool t_visited[maxN];

void dfs(int c, int p){
  t_visited[c] = true;
  t_depth[c] = ( p ? t_depth[p] + 1 : 0);
  for(int i : t_edge[c]){
    if(i == p) continue;
    dfs(i, c);
  }
}


int LCA(int x, int y){
  if(t_depth[x] < t_depth[y]) swap(x,y);
  int c = t_depth[x] - t_depth[y];
  F(18) if( (c >> i) & 1) x = ST[i][x];
  if(x == y) return x;
  RF(18){
    if( ST[i][x] && ST[i][y] && ST[i][x] != ST[i][y]){
      x = ST[i][x];
      y = ST[i][y];
    }
  }
  x = ST[0][x];
  y = ST[0][y];
  return x;
}

void process(int x, int y){
  int c = LCA(x,y);
  while( t_depth[x] > t_depth[c] ){
    if(dsu[1][x] != x){
      x = dsu[1][x];
    }else{
      merge(1, x, ST[0][x]);
      x = ST[0][x];
    }
  }
  while( t_depth[y] > t_depth[c] ){
    if(dsu[0][y] != y){
      y = dsu[0][y];
    }else{
      merge(0, y, ST[0][y]);
      y = ST[0][y];
    }
  }
}


signed main(){
  
  iota(dsu[0], dsu[0] + maxN, 0);
  iota(dsu[1], dsu[1] + maxN, 0);
  
  cin.tie(0);
  ios_base::sync_with_stdio(false);

  int n, m;
  cin >> n >> m;
  F(m){
    int x,y;
    cin >> x >> y;
    edge[x].pb(y);
    edge[y].pb(x);
    tab[i] = mp(x,y);
  }

  F(n) if(!visited[i+1]) tarjan(i+1, 0);
  
  Fi(x, m){
    auto [i,j] = tab[x];
    if(bcc[i] != bcc[j]){
      t_edge[bcc[i]].pb(bcc[j]);
      t_edge[bcc[j]].pb(bcc[i]);
      if(depth[bcc[i]] > depth[bcc[j]]){
        ST[0][bcc[i]] = fa[bcc[i]] = bcc[j];
      }else{
        ST[0][bcc[j]] = fa[bcc[j]] = bcc[i];
      }
    }
  }
  
  Fl(i, 1, n+1){
    if(!t_visited[bcc[i]]) dfs( bcc[i], 0);
  }

  Fl(i, 1, 18){
    Fi(j, maxN){
      ST[i][j] = ST[i-1][ST[i-1][j]];
    }
  }

  int p;
  cin >> p;
  
  F(p){
    int x,y;
    cin >> x >> y;
    x = bcc[x], y = bcc[y];
    process(x,y);
  }
  
  Fi(x, m){
    auto [i,j] = tab[x];
    i = bcc[i], j = bcc[j];
    if(i != j){
      if(query(0, i) == query(0, j)){
        if(t_depth[i] < t_depth[j]){
          ans[x] = 'R';
        }else{
          ans[x] = 'L';
        }
      }else if(query(1,i) == query(1, j)){
        if(t_depth[i] < t_depth[j]){
          ans[x] = 'L';
        }else{
          ans[x] = 'R';
        }
      }else{
        ans[x] = 'B';
      }
    }else{
      ans[x] = 'B';
    }
  }
  
  F(m) printf("%c", ans[i]);
   
  return 0;
}

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 12492 KB Output is correct
2 Correct 7 ms 12492 KB Output is correct
3 Correct 7 ms 12492 KB Output is correct
4 Correct 8 ms 12492 KB Output is correct
5 Correct 8 ms 12620 KB Output is correct
6 Correct 7 ms 12492 KB Output is correct
7 Correct 7 ms 12620 KB Output is correct
8 Correct 7 ms 12492 KB Output is correct
9 Correct 7 ms 12492 KB Output is correct
10 Correct 8 ms 12492 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 12492 KB Output is correct
2 Correct 7 ms 12492 KB Output is correct
3 Correct 7 ms 12492 KB Output is correct
4 Correct 8 ms 12492 KB Output is correct
5 Correct 8 ms 12620 KB Output is correct
6 Correct 7 ms 12492 KB Output is correct
7 Correct 7 ms 12620 KB Output is correct
8 Correct 7 ms 12492 KB Output is correct
9 Correct 7 ms 12492 KB Output is correct
10 Correct 8 ms 12492 KB Output is correct
11 Correct 38 ms 16472 KB Output is correct
12 Correct 40 ms 17812 KB Output is correct
13 Correct 45 ms 19268 KB Output is correct
14 Correct 51 ms 20940 KB Output is correct
15 Correct 59 ms 21568 KB Output is correct
16 Correct 70 ms 22368 KB Output is correct
17 Correct 67 ms 23852 KB Output is correct
18 Correct 72 ms 22368 KB Output is correct
19 Correct 68 ms 25076 KB Output is correct
20 Correct 52 ms 17408 KB Output is correct
21 Correct 41 ms 17756 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 12492 KB Output is correct
2 Correct 7 ms 12492 KB Output is correct
3 Correct 7 ms 12492 KB Output is correct
4 Correct 8 ms 12492 KB Output is correct
5 Correct 8 ms 12620 KB Output is correct
6 Correct 7 ms 12492 KB Output is correct
7 Correct 7 ms 12620 KB Output is correct
8 Correct 7 ms 12492 KB Output is correct
9 Correct 7 ms 12492 KB Output is correct
10 Correct 8 ms 12492 KB Output is correct
11 Correct 38 ms 16472 KB Output is correct
12 Correct 40 ms 17812 KB Output is correct
13 Correct 45 ms 19268 KB Output is correct
14 Correct 51 ms 20940 KB Output is correct
15 Correct 59 ms 21568 KB Output is correct
16 Correct 70 ms 22368 KB Output is correct
17 Correct 67 ms 23852 KB Output is correct
18 Correct 72 ms 22368 KB Output is correct
19 Correct 68 ms 25076 KB Output is correct
20 Correct 52 ms 17408 KB Output is correct
21 Correct 41 ms 17756 KB Output is correct
22 Correct 152 ms 24816 KB Output is correct
23 Correct 140 ms 24588 KB Output is correct
24 Correct 131 ms 24916 KB Output is correct
25 Correct 149 ms 29256 KB Output is correct
26 Correct 140 ms 25836 KB Output is correct
27 Correct 142 ms 24960 KB Output is correct
28 Correct 37 ms 15680 KB Output is correct
29 Correct 63 ms 19340 KB Output is correct
30 Correct 69 ms 19896 KB Output is correct
31 Correct 65 ms 19700 KB Output is correct
32 Correct 91 ms 23384 KB Output is correct