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Submission #1109440

# Submission time Handle Problem Language Result Execution time Memory
1109440 2024-11-06T17:29:37 Z simona1230 One-Way Streets (CEOI17_oneway) C++17
100 / 100
 125 ms 44480 KB 
#include <bits/stdc++.h>

using namespace std;
int n,m;
vector<int> v[200001],id[200001];
void read()
{
    cin>>n>>m;
    for(int i=1;i<=m;i++)
    {
        int x,y;
        cin>>x>>y;
        v[x].push_back(y);
        v[y].push_back(x);
        id[x].push_back(i);
        id[y].push_back(-i);
    }
}

int bridge[200001];
int t,in[200001];
int low[200001];

void dfs(int i,int p)
{
    low[i]=in[i]=++t;
    //cout<<i<<" "<<in[i]<<endl;

    for(int j=0;j<v[i].size();j++)
    {
        int nb=v[i][j];
        if(nb==p)continue;

        if(!in[nb])
        {
            dfs(nb,i);
            //cout<<i<<" > "<<nb<<" "<<low[nb]<<endl;
            low[i]=min(low[i],low[nb]);
            if(low[nb]>in[i])bridge[abs(id[i][j])]=1;
        }
        else low[i]=min(low[i],in[nb]);
    }
}

int num,c[200001];
vector<int> g[200001],idx[200001];

void dfs1(int i)
{
    c[i]=num;
    for(int j=0;j<v[i].size();j++)
    {
        int nb=v[i][j];
        if(!c[nb]&&!bridge[abs(id[i][j])])
        {
            dfs1(nb);
        }
        else if(c[nb]&&c[i]!=c[nb])
        {
            g[c[nb]].push_back(c[i]);
            g[c[i]].push_back(c[nb]);
            idx[c[nb]].push_back(-id[i][j]);
            idx[c[i]].push_back(id[i][j]);
        }
    }
}


int q;
int d[200001];
int sz[200001];
char ans[200001];
int hey[200001];
void dfs2(int i,int p)
{
    hey[i]=1;
    sz[i]=d[i];
    for(int j=0;j<g[i].size();j++)
    {
        int nb=g[i][j];
        if(p==nb)continue;

        dfs2(nb,i);
        if(sz[nb]==0)ans[abs(idx[i][j])]='B';
        else if(sz[nb]>0&&idx[i][j]>0||sz[nb]<0&&idx[i][j]<0)
            ans[abs(idx[i][j])]='L';
        else ans[abs(idx[i][j])]='R';
        sz[i]+=sz[nb];
    }
}

void solve()
{
    cin>>q;
    for(int i=1;i<=q;i++)
    {
        int x,y;
        cin>>x>>y;
        d[c[x]]++;
        d[c[y]]--;
    }

   /*for(int i=1;i<=n;i++)
        cout<<c[i]<<" ";
    cout<<endl;*/

    for(int i=1;i<=num;i++)
        if(!hey[i])dfs2(i,-1);
}

int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);

	read();
	for(int i=1;i<=n;i++)
        if(!in[i])dfs(i,-1);
    for(int i=1;i<=n;i++)
    {
        if(!c[i])
        {
            num++;
            dfs1(i);
        }
    }
    for(int i=1;i<=m;i++)
        ans[i]='B';

    solve();

    for(int i=1;i<=m;i++)
        cout<<ans[i];
    cout<<endl;
	return 0;
}

Compilation message

oneway.cpp: In function 'void dfs(int, int)':
oneway.cpp:29:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   29 |     for(int j=0;j<v[i].size();j++)
      |                 ~^~~~~~~~~~~~
oneway.cpp: In function 'void dfs1(int)':
oneway.cpp:51:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   51 |     for(int j=0;j<v[i].size();j++)
      |                 ~^~~~~~~~~~~~
oneway.cpp: In function 'void dfs2(int, int)':
oneway.cpp:78:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   78 |     for(int j=0;j<g[i].size();j++)
      |                 ~^~~~~~~~~~~~
oneway.cpp:85:25: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   85 |         else if(sz[nb]>0&&idx[i][j]>0||sz[nb]<0&&idx[i][j]<0)
      |                 ~~~~~~~~^~~~~~~~~~~~~

Subtask #1
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 22608 KB Output is correct
2 Correct 7 ms 22608 KB Output is correct
3 Correct 6 ms 22776 KB Output is correct
4 Correct 5 ms 22864 KB Output is correct
5 Correct 6 ms 22864 KB Output is correct
6 Correct 6 ms 22608 KB Output is correct
7 Correct 6 ms 22892 KB Output is correct
8 Correct 6 ms 22864 KB Output is correct
9 Correct 6 ms 22608 KB Output is correct
10 Correct 5 ms 22608 KB Output is correct

Subtask #2
30.0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 22608 KB Output is correct
2 Correct 7 ms 22608 KB Output is correct
3 Correct 6 ms 22776 KB Output is correct
4 Correct 5 ms 22864 KB Output is correct
5 Correct 6 ms 22864 KB Output is correct
6 Correct 6 ms 22608 KB Output is correct
7 Correct 6 ms 22892 KB Output is correct
8 Correct 6 ms 22864 KB Output is correct
9 Correct 6 ms 22608 KB Output is correct
10 Correct 5 ms 22608 KB Output is correct
11 Correct 39 ms 28488 KB Output is correct
12 Correct 41 ms 30024 KB Output is correct
13 Correct 63 ms 31428 KB Output is correct
14 Correct 62 ms 34120 KB Output is correct
15 Correct 83 ms 34800 KB Output is correct
16 Correct 96 ms 37884 KB Output is correct
17 Correct 100 ms 39752 KB Output is correct
18 Correct 98 ms 37928 KB Output is correct
19 Correct 94 ms 41004 KB Output is correct
20 Correct 41 ms 29512 KB Output is correct
21 Correct 43 ms 29512 KB Output is correct

Subtask #3
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 22608 KB Output is correct
2 Correct 7 ms 22608 KB Output is correct
3 Correct 6 ms 22776 KB Output is correct
4 Correct 5 ms 22864 KB Output is correct
5 Correct 6 ms 22864 KB Output is correct
6 Correct 6 ms 22608 KB Output is correct
7 Correct 6 ms 22892 KB Output is correct
8 Correct 6 ms 22864 KB Output is correct
9 Correct 6 ms 22608 KB Output is correct
10 Correct 5 ms 22608 KB Output is correct
11 Correct 39 ms 28488 KB Output is correct
12 Correct 41 ms 30024 KB Output is correct
13 Correct 63 ms 31428 KB Output is correct
14 Correct 62 ms 34120 KB Output is correct
15 Correct 83 ms 34800 KB Output is correct
16 Correct 96 ms 37884 KB Output is correct
17 Correct 100 ms 39752 KB Output is correct
18 Correct 98 ms 37928 KB Output is correct
19 Correct 94 ms 41004 KB Output is correct
20 Correct 41 ms 29512 KB Output is correct
21 Correct 43 ms 29512 KB Output is correct
22 Correct 114 ms 40776 KB Output is correct
23 Correct 123 ms 38984 KB Output is correct
24 Correct 125 ms 39328 KB Output is correct
25 Correct 105 ms 44480 KB Output is correct
26 Correct 103 ms 40264 KB Output is correct
27 Correct 106 ms 38984 KB Output is correct
28 Correct 35 ms 25928 KB Output is correct
29 Correct 53 ms 30280 KB Output is correct
30 Correct 50 ms 30540 KB Output is correct
31 Correct 68 ms 30792 KB Output is correct
32 Correct 71 ms 35656 KB Output is correct