Submission #314385

#	Time	Username	Problem	Language	Result	Execution time	Memory
314385		leaked	Lampice (COCI19_lampice)	C++14	42 / 110	3228 ms	28080 KiB

lampice

#include <bits/stdc++.h>
//#include "race.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)
//#define int long long
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=LLONG_MAX/2;
const ld eps = 1e-9;
const int ppp=73;
const int M=9999937;
auto rnd=bind(uniform_int_distribution<ll>(1,1e9),mt19937(time(0)));
short int gp[M];
vec<int> g[N];
bool used[N];
int dp[N];
int mult(int a,int b){
    return 1ll*a*b%M;
}
int plues(int a,int b){
    int x=(a+b);
    if(x<0)
        x+=M;
    if(x>M)
        x-=M;
    return x;
}
void add(int &a,int b){
    a+=b;
    if(a<0)
        a+=M;
    if(a>M)
        a-=M;
}
void recaclc(int v,int p){
    dp[v]=1;
    for(auto &z : g[v]){
        if(z^p && !used[z])
            recaclc(z,v),dp[v]+=dp[z];
    }
}
int get_cen(int v,int p,int sz){
    for(auto &z : g[v]){
        if(!used[z] && z^p && dp[z]>=(sz+1)/2)
            return get_cen(z,v,sz);
    }
    return v;
}
vec<int>a;
vec<int>c;
string s;
int pp[N];
int Hd[N];
int Hup[N];
int TO[N];
bool ok;
int done;
void dfs(int v,int p,int len,int hd,int hup,int dl){
    if(ok)
        return;
    a.emplace_back(v);
    hd=plues(mult(s[v]-'a'+1,pp[dl-1]),hd);
    hup=plues(mult(hup,ppp),s[v]-'a'+1);
    Hd[v]=hd;
    Hup[v]=hup;
    TO[v]=dl;
    if((dl-1)<=len/2){
        c.pb(mult(plues(hd,-(s[a[0]]-'a'+1)),pp[N-2]));
    }
    if(dl>=(len+1)/2 && dl<len){
        int rem=len-dl;
        int mh=hd;
//        debug()<<imie(gp);
        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]);
                ok|=gp[mh];
            }
        }
        else{
            mh=mult(mh,pp[N-1]);
            ok|=gp[mh];
        }
    }
    else if(dl>=len){
        if(dl!=len){
            add(hup,-mult(pp[len],s[a[dl-len-1]]-'a'+1));
            int u=a[dl-len-1];
            add(hd,-mult(pp[TO[u]-1],s[u]-'a'+1));
        }
        ok|=(mult(hup,pp[N-1])==mult(hd,pp[N-(dl-len)-1]));
    }
    for(auto &z : g[v]){
        if(!used[z] && z!=p){
            dfs(z,v,len,hd,hup,dl+1);
        }
    }
    a.pop_back();
}
vec<int>lol[N];
void calc(int v,int len){
    recaclc(v,v);
    v=get_cen(v,v,dp[v]);
    used[v]=1;
    a.pb(v);
    Hd[v]=s[v]-'a'+1;
    Hup[v]=s[v]-'a'+1;
    vec<vec<int>>lol(sz(g[v]),vec<int>());
    int i=-1;
    for(auto &z : g[v]){
        i++;
        if(used[z]) continue;
        dfs(z,v,len,s[v]-'a'+1,s[v]-'a'+1,2);
        for(auto &q : c){
            gp[q]++;
        }
        lol[i]=c;
        c.clear();
    }
    for(i=0;i<sz(g[v]);++i){
        auto z=g[v][i];
        if(used[z]) continue;
        for(auto &q : lol[i]){
            gp[q]--;
        }
        dfs(z,v,len,s[v]-'a'+1,s[v]-'a'+1,2);
        c.clear();
        lol[i].clear();
    }
    a.clear();
    if(ok)
        return ;
    for(auto &z : g[v]){
        if(!used[z])
            calc(z,len);
    }
}
int n;
signed main(){
    fast_io;
//    ifstream cin("input.txt");
//    gp.reserve(1<<20);
//    cout << fixed << LLONG_MAX/3 << "\n" << 1e18;
    cin>>n;
    cin>>s;
    pp[0]=1;
    for(int i = 1 ;i < N; ++i)
        pp[i]=mult(ppp,pp[i-1]);
    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<2;i++){
        int l=1,r=n/2+1;
        while(l!=r){
            fill(used,used+n,false);
            ok=0;
            int tm=(l+r)>>1;
            calc(0,2*tm+i);
            if(ok)
                l=tm+1;
            else
                r=tm;
        }
        l--;
//        umax(ans,2*l+i);
        ans=max(ans,2*l+i);
    }
    cout<<ans;
    return 0;
}
/*
7
abacaba
1 2
2 3
3 4
4 5
5 6
6 7
7 1
*/

• Subtask 1: 17 / 17
• Subtask 2: 25 / 25
• Subtask 3: 0 / 31
• Subtask 4: 0 / 37