#include <bits/stdc++.h>
#define union khoaphamdangyeuhihixd
using namespace std;
int h1, w, p, q;
int last[2005][2005], dist[2005][2005];
queue<pair<int, int> > b;
string s[2005];
vector<pair<int, int> > adj[200005];
int dx[]={0, 1, 0, -1};
int dy[]={-1, 0, 1, 0};
vector<pair<int, pair<int, int> > > edges;
int f[200005], h[200005];
pair<int, int> anc[200005][20];
int find(int i)
{
return f[i]==i ? f[i] : find(f[i]);
}
void union(int i, int j)
{
f[find(i)]=find(j);
}
bool check(int a, int b)
{
if(a>0 && b>0 && a<=h1 && b<=w && s[a][b]!='#' && last[a][b]==0)
{
return true;
}
return false;
}
void bfs()
{
while(b.size())
{
pair<int, int> fr=b.front();
b.pop();
for(int i=0; i<4; i++)
{
int ax=fr.first+dx[i], ay=fr.second+dy[i], ck=check(ax, ay);
if(ck)
{
last[ax][ay]=last[fr.first][fr.second];
dist[ax][ay]=dist[fr.first][fr.second]+1;
b.push({ax, ay});
}
else if(last[ax][ay]!=0)
{
edges.push_back({dist[ax][ay]+dist[fr.first][fr.second],{last[ax][ay], last[fr.first][fr.second]}});
}
}
}
}
void kruskal()
{
sort(edges.begin(), edges.end());
for(auto i:edges)
{
if(find(i.second.second)!=find(i.second.first))
{
union(i.second.first, i.second.second);
adj[i.second.first].push_back({i.second.second, i.first});
adj[i.second.second].push_back({i.second.first, i.first});
}
}
}
bool visited[200005];
void dfs(int node, int fa)
{
visited[node]=1;
h[node]=h[fa]+1;
anc[node][0].first=fa;
for(int i=1; i<=19; i++)
{
anc[node][i].first=anc[anc[node][i-1].first][i-1].first;
anc[node][i].second=max(anc[node][i-1].second, anc[anc[node][i-1].first][i-1].second);
}
for(auto i:adj[node])
{
if(i.first==fa)
{
continue;
}
anc[i.first][0].second=i.second;
dfs(i.first, node);
}
}
int lca(int u, int v)
{
// cout<<u<<" "<<v<<endl;
int lel=0;
if(h[u]<h[v])
{
swap(u, v);
}
for(int i=18; i>=0; i--)
{
if(h[anc[u][i].first]<h[v]) continue;
lel=max(lel, anc[u][i].second);
u=anc[u][i].first;
}
// cout<<u<<endl;
if(u==v) return lel;
for(int i=18; i>=0; i--)
{
if(anc[u][i].first==anc[v][i].first) continue;
lel=max(lel, max(anc[u][i].second, anc[v][i].second));
u=anc[u][i].first;
v=anc[v][i].first;
}
return max(lel, max(anc[u][0].second, anc[v][0].second));
}
signed main()
{
cin>>h1>>w>>p>>q;
for(int i=1; i<=p; i++)
{
f[i]=i;
}
for(int i=1; i<=h1; i++)
{
cin>>s[i];
s[i]='!'+s[i]+'!';
}
for(int i=1; i<=p; i++)
{
int u, v;
cin>>u>>v;
b.push({u, v});
last[u][v]=i;
}
bfs();
kruskal();
for(int i=1; i<=p; i++)
{
if(!visited[i])
{
dfs(i, i);
}
}
// for(int i=1; i<=h1; i++)
// {
// for(int j=1; j<=w; j++)
// {
// cout<<last[i][j]<<" ";
// }
// cout<<endl;
// }
for(int i=1; i<=q; i++)
{
int u, v;
cin>>u>>v;
// cout<<find(u)<<" "<<find(v)<<endl;
if(find(u)==find(v)) cout<<lca(u, v)<<endl;
else cout<<-1<<endl;
}
}
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
18 ms |
6204 KB |
Output is correct |
2 |
Correct |
20 ms |
7360 KB |
Output is correct |
3 |
Correct |
25 ms |
7928 KB |
Output is correct |
4 |
Correct |
731 ms |
8580 KB |
Output is correct |
5 |
Correct |
740 ms |
8568 KB |
Output is correct |
6 |
Correct |
733 ms |
8176 KB |
Output is correct |
7 |
Correct |
724 ms |
8328 KB |
Output is correct |
8 |
Correct |
746 ms |
8948 KB |
Output is correct |
9 |
Correct |
721 ms |
8664 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
84 ms |
26544 KB |
Output is correct |
2 |
Correct |
170 ms |
16100 KB |
Output is correct |
3 |
Correct |
962 ms |
93956 KB |
Output is correct |
4 |
Correct |
1941 ms |
143428 KB |
Output is correct |
5 |
Correct |
2401 ms |
144000 KB |
Output is correct |
6 |
Correct |
989 ms |
93888 KB |
Output is correct |
7 |
Correct |
2176 ms |
143740 KB |
Output is correct |
8 |
Correct |
2338 ms |
144020 KB |
Output is correct |
9 |
Correct |
3601 ms |
242932 KB |
Output is correct |
10 |
Correct |
1109 ms |
143224 KB |
Output is correct |
11 |
Correct |
1359 ms |
143548 KB |
Output is correct |
12 |
Correct |
702 ms |
83928 KB |
Output is correct |
13 |
Correct |
786 ms |
86360 KB |
Output is correct |
14 |
Correct |
722 ms |
83824 KB |
Output is correct |
15 |
Correct |
779 ms |
84992 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
83 ms |
26596 KB |
Output is correct |
2 |
Correct |
118 ms |
15304 KB |
Output is correct |
3 |
Correct |
813 ms |
93756 KB |
Output is correct |
4 |
Correct |
1804 ms |
143624 KB |
Output is correct |
5 |
Correct |
2438 ms |
144004 KB |
Output is correct |
6 |
Correct |
4075 ms |
242996 KB |
Output is correct |
7 |
Correct |
1373 ms |
143188 KB |
Output is correct |
8 |
Correct |
1897 ms |
143688 KB |
Output is correct |
9 |
Correct |
763 ms |
83928 KB |
Output is correct |
10 |
Correct |
816 ms |
85564 KB |
Output is correct |
11 |
Correct |
785 ms |
61612 KB |
Output is correct |
# |
Verdict |
Execution time |
Memory |
Grader output |
1 |
Correct |
2141 ms |
94068 KB |
Output is correct |
2 |
Correct |
4357 ms |
126868 KB |
Output is correct |
3 |
Correct |
1226 ms |
143316 KB |
Output is correct |
4 |
Execution timed out |
5097 ms |
148604 KB |
Time limit exceeded |
5 |
Halted |
0 ms |
0 KB |
- |