#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "debug.h"
#else
#define debug(...)
#endif
using pii=array<int,2>;
using tii=array<int,3>;
const int N=3005;
int n,r,a,b,dep[N],p[N],q[N],L[N],pA[N],subA[N];
vector<int> dp[N];
vector<int> dp2[N];
int dp3[N][N],dp4[N][N];
vector<int> g[N],c[N],dA[N];
void dfs0(int u){
L[dep[u]]=u;
if(dep[u]>=a){
pA[u]=L[dep[u]-a];
subA[u]=L[dep[u]-a+1];
dA[pA[u]].push_back(u);
}
int idx=0;
for(int v: g[u]) if(p[u]!=v){
dep[v]=dep[u]+1;
p[v]=u;
q[v]=++idx;
c[u].push_back(v);
dfs0(v);
}
}
int dfs1(int u,int d);
int dfs2(int u,int d);
int Get(int u,int k){
int &ret=dp[u][k];
if(ret) return ret;
for(int i=0;i<(int)dA[u].size();i++){
int v=dA[u][i];
if(q[subA[v]]==k) continue;
if(dp2[u][i]){
ret=max(ret,dp2[u][i]);
continue;
}
int val=dfs1(v,b),w=v,d=0,e=0;
while(d<b){
e=q[w];
w=p[w];
d++;
val=min(val,Get(w,e));
if(d<b) for(int i=0;i<(int)c[w].size();i++) if(i+1!=e) val=min(val,dfs1(c[w][i],b-d-1));
}
dp2[u][i]=val;
ret=max(ret,val);
}
if(!ret){
ret=u;
for(int i=0;i<(int)c[u].size();i++) if(i+1!=k) ret=min(ret,dfs2(c[u][i],b-1));
}
debug(u,k,ret);
return ret;
}
int dfs1(int u,int d){
int &ret=dp3[u][d];
if(ret) return ret;
ret=Get(u,0);
if(d>=1) for(int v: c[u]) ret=min(ret,dfs1(v,d-1));
debug(u,d,0,ret);
return ret;
}
int dfs2(int u,int d){
int &ret=dp4[u][d];
if(ret) return ret;
ret=u;
if(d>=1) for(int v: c[u]) ret=min(ret,dfs2(v,d-1));
debug(u,d,1,ret);
return ret;
}
int main(){
ios::sync_with_stdio(false); cin.tie(0);
cin>>n>>r>>a>>b;
if(a<=b){
cout<<"1\n";
return 0;
}
for(int u,v,i=1;i<n;i++){
cin>>u>>v;
g[u].push_back(v);
g[v].push_back(u);
}
dfs0(r);
for(int i=1;i<=n;i++){
dp[i].resize(c[i].size()+1);
dp2[i].resize(dA[i].size());
}
cout<<Get(r,0);
return 0;
}
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
600 KB |
Output is correct |
2 |
Correct |
0 ms |
604 KB |
Output is correct |
3 |
Correct |
0 ms |
604 KB |
Output is correct |
4 |
Correct |
0 ms |
604 KB |
Output is correct |
5 |
Correct |
0 ms |
604 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
65 ms |
34384 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
2652 KB |
Output is correct |
2 |
Correct |
1 ms |
2652 KB |
Output is correct |
3 |
Correct |
1 ms |
2648 KB |
Output is correct |
4 |
Correct |
1 ms |
2652 KB |
Output is correct |
5 |
Correct |
1 ms |
2652 KB |
Output is correct |
6 |
Correct |
1 ms |
2732 KB |
Output is correct |
7 |
Correct |
1 ms |
2908 KB |
Output is correct |
8 |
Correct |
1 ms |
1884 KB |
Output is correct |
9 |
Correct |
0 ms |
604 KB |
Output is correct |
10 |
Correct |
1 ms |
1884 KB |
Output is correct |
11 |
Correct |
1 ms |
1884 KB |
Output is correct |
12 |
Correct |
0 ms |
860 KB |
Output is correct |
13 |
Correct |
1 ms |
860 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
2652 KB |
Output is correct |
2 |
Correct |
1 ms |
2652 KB |
Output is correct |
3 |
Correct |
1 ms |
2648 KB |
Output is correct |
4 |
Correct |
1 ms |
2652 KB |
Output is correct |
5 |
Correct |
1 ms |
2652 KB |
Output is correct |
6 |
Correct |
1 ms |
2732 KB |
Output is correct |
7 |
Correct |
1 ms |
2908 KB |
Output is correct |
8 |
Correct |
1 ms |
1884 KB |
Output is correct |
9 |
Correct |
0 ms |
604 KB |
Output is correct |
10 |
Correct |
1 ms |
1884 KB |
Output is correct |
11 |
Correct |
1 ms |
1884 KB |
Output is correct |
12 |
Correct |
0 ms |
860 KB |
Output is correct |
13 |
Correct |
1 ms |
860 KB |
Output is correct |
14 |
Correct |
8 ms |
20316 KB |
Output is correct |
15 |
Correct |
8 ms |
19548 KB |
Output is correct |
16 |
Correct |
8 ms |
21720 KB |
Output is correct |
17 |
Correct |
8 ms |
20828 KB |
Output is correct |
18 |
Correct |
7 ms |
20176 KB |
Output is correct |
19 |
Correct |
8 ms |
19492 KB |
Output is correct |
20 |
Correct |
10 ms |
23652 KB |
Output is correct |
21 |
Correct |
5 ms |
13148 KB |
Output is correct |
22 |
Correct |
0 ms |
604 KB |
Output is correct |
23 |
Correct |
9 ms |
18440 KB |
Output is correct |
24 |
Correct |
9 ms |
22496 KB |
Output is correct |
25 |
Correct |
12 ms |
23384 KB |
Output is correct |
26 |
Correct |
6 ms |
13148 KB |
Output is correct |
27 |
Correct |
4 ms |
12936 KB |
Output is correct |
28 |
Correct |
5 ms |
13148 KB |
Output is correct |
29 |
Correct |
5 ms |
13148 KB |
Output is correct |
30 |
Correct |
56 ms |
23144 KB |
Output is correct |
31 |
Correct |
56 ms |
23088 KB |
Output is correct |
32 |
Correct |
57 ms |
23132 KB |
Output is correct |
33 |
Correct |
13 ms |
14428 KB |
Output is correct |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Runtime error |
23 ms |
12368 KB |
Execution killed with signal 11 |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
2652 KB |
Output is correct |
2 |
Correct |
1 ms |
2652 KB |
Output is correct |
3 |
Correct |
1 ms |
2648 KB |
Output is correct |
4 |
Correct |
1 ms |
2652 KB |
Output is correct |
5 |
Correct |
1 ms |
2652 KB |
Output is correct |
6 |
Correct |
1 ms |
2732 KB |
Output is correct |
7 |
Correct |
1 ms |
2908 KB |
Output is correct |
8 |
Correct |
1 ms |
1884 KB |
Output is correct |
9 |
Correct |
0 ms |
604 KB |
Output is correct |
10 |
Correct |
1 ms |
1884 KB |
Output is correct |
11 |
Correct |
1 ms |
1884 KB |
Output is correct |
12 |
Correct |
0 ms |
860 KB |
Output is correct |
13 |
Correct |
1 ms |
860 KB |
Output is correct |
14 |
Correct |
8 ms |
20316 KB |
Output is correct |
15 |
Correct |
8 ms |
19548 KB |
Output is correct |
16 |
Correct |
8 ms |
21720 KB |
Output is correct |
17 |
Correct |
8 ms |
20828 KB |
Output is correct |
18 |
Correct |
7 ms |
20176 KB |
Output is correct |
19 |
Correct |
8 ms |
19492 KB |
Output is correct |
20 |
Correct |
10 ms |
23652 KB |
Output is correct |
21 |
Correct |
5 ms |
13148 KB |
Output is correct |
22 |
Correct |
0 ms |
604 KB |
Output is correct |
23 |
Correct |
9 ms |
18440 KB |
Output is correct |
24 |
Correct |
9 ms |
22496 KB |
Output is correct |
25 |
Correct |
12 ms |
23384 KB |
Output is correct |
26 |
Correct |
6 ms |
13148 KB |
Output is correct |
27 |
Correct |
4 ms |
12936 KB |
Output is correct |
28 |
Correct |
5 ms |
13148 KB |
Output is correct |
29 |
Correct |
5 ms |
13148 KB |
Output is correct |
30 |
Correct |
56 ms |
23144 KB |
Output is correct |
31 |
Correct |
56 ms |
23088 KB |
Output is correct |
32 |
Correct |
57 ms |
23132 KB |
Output is correct |
33 |
Correct |
13 ms |
14428 KB |
Output is correct |
34 |
Runtime error |
24 ms |
12380 KB |
Execution killed with signal 11 |
35 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Correct |
1 ms |
600 KB |
Output is correct |
2 |
Correct |
0 ms |
604 KB |
Output is correct |
3 |
Correct |
0 ms |
604 KB |
Output is correct |
4 |
Correct |
0 ms |
604 KB |
Output is correct |
5 |
Correct |
0 ms |
604 KB |
Output is correct |
6 |
Runtime error |
65 ms |
34384 KB |
Execution killed with signal 11 |
7 |
Halted |
0 ms |
0 KB |
- |