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ID | 题目 | 提交者 | 结果 | 用时 | 内存 | 语言 | 文件大小 | 提交时间 | 测评时间 |
---|---|---|---|---|---|---|---|---|---|
#193692 | #7513. Palindromic Beads | PhantomThreshold# | WA | 2ms | 32716kb | C++20 | 4.0kb | 2023-09-30 17:43:26 | 2023-09-30 17:43:27 |
Judging History
answer
#include<bits/stdc++.h>
#define ll long long
//#define int long long
using namespace std;
const int maxn = 205000;
const int maxp = 100005*18*18;
const int maxd = 18;
vector<int>V[maxn],col[maxn];
int n;
int ci[maxn];
int dfn[maxn],dfi,siz[maxn],c1[maxn],sum1[maxn];
int fa[maxn][maxd],dep[maxn];
void dfs(const int x)
{
for(int d=1;d<maxd;d++)
fa[x][d]= fa[ fa[x][d-1] ][d-1];
sum1[x]=sum1[fa[x][0]]+c1[x];
dfn[x]=++dfi;
siz[x]=1;
for(auto y:V[x]) if(y!=fa[x][0])
{
fa[y][0]=x;
dep[y]=dep[x]+1;
dfs(y);
siz[x]+=siz[y];
}
}
int lca(int x,int y)
{
if(dep[x]<dep[y]) swap(x,y);
for(int d=maxd-1;d>=0;d--) if(dep[x]-dep[y]>=(1<<d))
x=fa[x][d];
if(x==y) return x;
for(int d=maxd-1;d>=0;d--) if(fa[x][d]!=fa[y][d])
x=fa[x][d],y=fa[y][d];
return fa[x][0];
}
vector< pair<int,int> >Va[maxn];
inline void up(int &a,const int &b){ if(a<b)a=b; }
struct segment1
{
int tot;
int seg[maxp],lc[maxp],rc[maxp];
void init()
{
tot=0;
}
int newnode()
{
++tot;
seg[tot]=lc[tot]=rc[tot]=0;
return tot;
}
int lx,rx,loc,c;
void upd(int &x,const int l,const int r)
{
if(!x) x=newnode();
up(seg[x],c);
if(l==r) return;
int mid=(l+r)>>1;
if(loc<=mid) upd(lc[x],l,mid);
else upd(rc[x],mid+1,r);
}
int query(const int x,const int l,const int r)
{
if(rx<l||r<lx||!x) return 0;
if(lx<=l&&r<=rx) return seg[x];
int mid=(l+r)>>1;
return max(query(lc[x],l,mid),query(rc[x],mid+1,r));
}
}seg0;
struct segment0
{
int seg[maxn<<2];
int lx,rx,ly,ry;
int updx,updy,updc;
void upd(const int x,const int l,const int r)
{
seg0.loc=updy,seg0.c=updc;
seg0.upd(seg[x],1,n);
if(l==r) return;
int mid=(l+r)>>1,lc=x<<1,rc=lc|1;
if(updx<=mid) upd(lc,l,mid);
else upd(rc,mid+1,r);
}
int query(const int x,const int l,const int r)
{
if(rx<l||r<lx) return 0;
if(lx<=l&&r<=rx)
{
seg0.lx=ly,seg0.rx=ry;
return seg0.query(seg[x],1,n);
}
int mid=(l+r)>>1,lc=x<<1,rc=lc|1;
return max(query(lc,l,mid),query(rc,mid+1,r));
}
}seg1;
signed main()
{
ios_base::sync_with_stdio(false);
cin.tie(0);
cin>>n;
for(int i=1;i<=n;i++)
{
cin>>ci[i];
col[ci[i]].emplace_back(i);
}
for(int i=1;i<n;i++)
{
int x,y; cin>>x>>y;
V[x].push_back(y);
V[y].push_back(x);
}
for(int i=1;i<=n;i++) c1[i]= col[ci[i]].size()==1;
dep[1]=1; dfs(1);
for(int i=1;i<=n;i++) if(col[i].size()==2)
{
int x=col[i][0],y=col[i][1];
int dis= dep[x]+dep[y]-2*dep[lca(x,y)];
Va[dis].emplace_back( x,y );
}
seg0.init();
int ans=1;
for(int d=n;d>=1;d--)
{
for(auto [x,y]:Va[d])
{
if(dfn[x]>dfn[y]) swap(x,y);
if(dfn[x]<dfn[y] && dfn[x]+siz[x]>dfn[y])
{
int val=0;
seg1.lx=1,seg1.rx=dfn[x]-1;
seg1.ly=dfn[y]+1,seg1.ry=dfn[y]+siz[y]-1;
if(seg1.lx<=seg1.rx && seg1.ly<=seg1.ry)
up(val, seg1.query(1,1,n) );
seg1.lx=dfn[x]+1,seg1.rx=dfn[y]-1;
if(seg1.lx<=seg1.rx && seg1.ly<=seg1.ry)
up(val, seg1.query(1,1,n) );
seg1.lx=dfn[y]+1,seg1.rx=dfn[y]+siz[y]-1;
seg1.ly=dfn[y]+siz[y],seg1.ry=dfn[x]+siz[x]-1;
if(seg1.lx<=seg1.rx && seg1.ly<=seg1.ry)
up(val, seg1.query(1,1,n) );
seg1.ly=dfn[x]+siz[x],seg1.ry=n;
if(seg1.lx<=seg1.rx && seg1.ly<=seg1.ry)
up(val, seg1.query(1,1,n) );
val++;
seg1.updx=dfn[x],seg1.updy=dfn[y],seg1.updc=val;
seg1.upd(1,1,n);
int ff=x;
int tc= d>1; //( sum1[x]+sum1[y]-sum1[ff]-sum1[fa[ff][0]]-c1[x]-c1[y] )>0;
up(ans,val*2+tc);
}
else
{
int val=0;
seg1.lx=dfn[x]+1,seg1.rx=dfn[x]+siz[x]-1;
seg1.ly=dfn[y]+1,seg1.ry=dfn[y]+siz[y]-1;
if(seg1.lx<=seg1.rx && seg1.ly<=seg1.ry)
up(val, seg1.query(1,1,n) );
val++;
seg1.updx=dfn[x],seg1.updy=dfn[y],seg1.updc=val;
seg1.upd(1,1,n);
int ff=lca(x,y);
int tc= d>1; //( sum1[x]+sum1[y]-sum1[ff]-sum1[fa[ff][0]]-c1[x]-c1[y] )>0;
up(ans,val*2+tc);
}
}
}
cout<<ans<<endl;
return 0;
}
详细
Test #1:
score: 100
Accepted
time: 0ms
memory: 32512kb
input:
4 1 1 2 2 1 2 2 3 2 4
output:
3
result:
ok single line: '3'
Test #2:
score: 0
Accepted
time: 0ms
memory: 30996kb
input:
5 1 3 2 2 1 1 2 2 3 3 4 4 5
output:
4
result:
ok single line: '4'
Test #3:
score: 0
Accepted
time: 0ms
memory: 29988kb
input:
6 1 1 2 2 3 3 1 2 2 3 3 4 4 5 5 6
output:
2
result:
ok single line: '2'
Test #4:
score: 0
Accepted
time: 0ms
memory: 26028kb
input:
6 1 2 3 4 5 6 1 2 2 3 3 4 4 5 5 6
output:
1
result:
ok single line: '1'
Test #5:
score: -100
Wrong Answer
time: 2ms
memory: 32716kb
input:
2000 845 1171 345 282 1181 625 754 289 681 493 423 840 1494 318 266 1267 967 379 135 14 39 191 60 972 116 1216 1205 19 194 185 1360 861 379 430 1262 1151 756 65 389 488 277 53 1283 1438 101 1465 195 714 737 980 80 298 961 1326 163 1163 1317 1152 992 35 334 802 1502 486 710 234 555 88 1278 146 46 696...
output:
7
result:
wrong answer 1st lines differ - expected: '5', found: '7'