Submission #315754

# Submission time Handle Problem Language Result Execution time Memory
315754 2020-10-23T21:14:30 Z leaked Lampice (COCI19_lampice) C++14
42 / 110
5000 ms 31736 KB
#include <bits/stdc++.h>
//#include "debug.h"
//    #pragma GCC optimize("-O3")
//    #pragma GCC optimize("no-stack-protector")
//    #pragma GCC optimize("fast-math")
//    #pragma GCC optimize("Ofast")
//    #pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx")
//    #pragma GCC target("avx,avx2,fma")
//    #pragma GCC optimization ("unroll-loops")
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define fi first
#define f first
#define s second
#define se second
#define vec vector
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define pb push_back
#define sz(x) (int)x.size()
#define pw(x) (1ll<<x)
#define p_b push_back
#define m_p make_pair
#define fast_io ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0)
#define sq(x) (x)*(x)
using namespace std;
using namespace __gnu_pbds;
typedef pair<long long, long long> PII;
typedef pair<int, int> pii;
typedef long double ld;
typedef long long ll;
typedef pair<long long, long long > pll;
//template <typename T> umax(T &a, T b){return (a<b ? a=b,1 : 0);}
//template <typename T> umin(T &a, T b){return (a>b ? a=b,1 : 0);}
typedef tree<pii,null_type,less<pii>,rb_tree_tag,tree_order_statistics_node_update> o_set;
const int N=5e4+5;
const ll inf=1e9;
const ld eps = 1e-9;
const int ppp=73;
const int M=99999837;
const ll tx[4]={-1,1,0,0};
const ll ty[4]={0,0,-1,1};
const char rev_to[4]={'U','D','L','R'};
auto rnd=bind(uniform_int_distribution<ll>(1,1e9),mt19937(time(0)));
int dp[N],TO[N];
bool used[N];
vec<int>g[N];
int pp[N];
void recalc(int v,int p){
    dp[v]=1;
    for(auto &z :  g[v]){
        if(!used[z] && z!=p){
            recalc(z,v);
            dp[v]+=dp[z];
        }
    }
}
int get_cen(int v,int p,int sz){
    for(auto &z : g[v]){
        if(z^p && !used[z] && dp[z]>=sz/2){
            return get_cen(z,v,sz);
        }
    }
    return v;
}
int sum(const int &a,const int &b){
    int x=(a+b);
    if(x>=M)
        x-=M;
    if(x<0)
        x+=M;
    return x;
}
void add(int &a,const int &b){
    int x=(a+b);
    if(x<0)
        x+=M;
    if(x>=M)
        x-=M;
    a=x;
}
int mult(const int &a,const int &b){
    return 1ll*a*b%M;
}
int ok;
gp_hash_table<int,int> gp[N];
int len,n,m;
vec<int>hd;
string s;
int Hd[N],Hup[N];
void calc_hd(int v,int p,int to,int dst){
    if(dst>(len/2))
        return;
    Hd[v]=sum(mult(s[v]-'a'+1,pp[dst-1]),Hd[p]);
    gp[dst][mult(Hd[v],pp[N-1])]+=to;
//    debug()<<imie(v)imie(mult(Hd[v],pp[N-dst-1]));
//    if(dst<=(len/2)){
       for(auto &z : g[v]){
            if(!used[z] && z^p){
                calc_hd(z,v,to,dst+1);
            }
        }
//    }
}
vec<int>a;
void calc_hupd(int v,int p,int dl){
    a.pb(v);
    Hup[v]=sum(mult(ppp,Hup[p]),s[v]-'a'+1);
    Hd[v]=sum(mult(s[v]-'a'+1,pp[dl-1]),Hd[p]);
//    debug()<<imie(v)imie(Hd[v])imie(Hup[v]);
    if(dl>=(len+1)/2 && dl<len){
        int rem=len-dl;
        int mh=Hd[v];
        if(dl-rem){
            int pr=a[dl-rem-1];
            add(mh,-Hd[pr]);
            if(Hd[pr]==Hup[pr]){
                mh=mult(mh,pp[N-(dl-rem)-1]);
//                debug()<<imie(rem)imie(gp[rem])imie(mh);
                ok|=gp[rem][mh];
            }
        }
        else{
            mh=mult(mh,pp[N-1]);
            ok|=gp[rem][mh];
        }
    }
    else if(dl>=len){
        if(dl!=len){
            add(Hup[v],-mult(pp[len],s[a[dl-len-1]]-'a'+1));
            int u=a[dl-len-1];
            add(Hd[v],-mult(pp[TO[u]-1],s[u]-'a'+1));
        }
        ok|=(mult(Hup[v],pp[N-1])==mult(Hd[v],pp[N-(dl-len)-1]));
    }
    for(auto &z : g[v]){
        if(!used[z] && z^p){
            TO[v]=z;
            calc_hupd(z,v,dl+1);
        }
    }
    a.pop_back();
}
void dfs(int v){
    recalc(v,v);
    v=get_cen(v,v,dp[v]);
    used[v]=1;
    Hd[v]=s[v]-'a'+1;
    Hup[v]=s[v]-'a'+1;
    a.pb(v);
    for(int i = 1; i >=-1; --i){
        if(!i)
            continue;
        for(auto &z : g[v]){
            if(!used[z]){
                TO[v]=z;
                if(i==1){
                    Hd[v]=s[v]-'a'+1;
                    calc_hupd(z,v,2);
                    Hd[v]=0;
                    calc_hd(z,v,i,1);
                }
                else{
                    Hd[v]=0;
                    calc_hd(z,v,i,1);
                    Hd[v]=s[v]-'a'+1;
                    calc_hupd(z,v,2);
                }
//                cout<<endl;
            }
        }
//        reverse(all(g[v]));

    }
    a.pop_back();
     if(ok)
        return ;
    for(auto &z : g[v]){
        if(!used[z])
            dfs(z);
    }
}
signed main()
{
    fast_io;
    pp[0]=1;
    for(int i = 1 ; i < N; ++i)
        pp[i]=mult(pp[i-1],ppp);
    cin>>n;
    cin>>s;
    for(int i = 1 ; i < n; i++){
        int v,u;
        cin>>v>>u;--v;--u;
        g[v].pb(u);
        g[u].pb(v);
    }
    int ans=1;
    for(int i = 0 ; i <= 1 ;i ++){
        int l=1,r=n/2+1;
        while(l!=r){
            int mid=(l+r)>>1;
            len=2*mid+i;
            ok=0;
            fill(used,used+n,false);
            dfs(0);
            if(ok){
                l=mid+1;
            }
            else{
                r=mid;
            }
        }
        l--;
        ans=max(ans,2*l+i);
    }
    cout<<ans;
    return 0;
}
/*
4
abba
1 2
2 3
3 4
*/
# Verdict Execution time Memory Grader output
1 Correct 18 ms 12288 KB Output is correct
2 Correct 22 ms 12416 KB Output is correct
3 Correct 43 ms 12672 KB Output is correct
4 Correct 56 ms 12544 KB Output is correct
5 Correct 14 ms 12416 KB Output is correct
6 Correct 14 ms 12288 KB Output is correct
7 Correct 14 ms 12288 KB Output is correct
# Verdict Execution time Memory Grader output
1 Correct 2320 ms 29568 KB Output is correct
2 Correct 1794 ms 26360 KB Output is correct
3 Correct 1303 ms 24056 KB Output is correct
4 Correct 1416 ms 24824 KB Output is correct
5 Correct 2353 ms 30776 KB Output is correct
6 Correct 293 ms 17400 KB Output is correct
# Verdict Execution time Memory Grader output
1 Execution timed out 5068 ms 31736 KB Time limit exceeded
2 Halted 0 ms 0 KB -
# Verdict Execution time Memory Grader output
1 Correct 18 ms 12288 KB Output is correct
2 Correct 22 ms 12416 KB Output is correct
3 Correct 43 ms 12672 KB Output is correct
4 Correct 56 ms 12544 KB Output is correct
5 Correct 14 ms 12416 KB Output is correct
6 Correct 14 ms 12288 KB Output is correct
7 Correct 14 ms 12288 KB Output is correct
8 Correct 2320 ms 29568 KB Output is correct
9 Correct 1794 ms 26360 KB Output is correct
10 Correct 1303 ms 24056 KB Output is correct
11 Correct 1416 ms 24824 KB Output is correct
12 Correct 2353 ms 30776 KB Output is correct
13 Correct 293 ms 17400 KB Output is correct
14 Execution timed out 5068 ms 31736 KB Time limit exceeded
15 Halted 0 ms 0 KB -