oj.uz

Submission #668131

# Submission time Handle Problem Language Result Execution time Memory
668131 2022-12-02T21:16:38 Z jeroenodb Lampice (COCI19_lampice) C++17
110 / 110
 2672 ms 9996 KB 
#include "bits/stdc++.h"
using namespace std;
#define all(x) begin(x),end(x)
template<typename A, typename B> ostream& operator<<(ostream &os, const pair<A, B> &p) { return os << '(' << p.first << ", " << p.second << ')'; }
template<typename T_container, typename T = typename enable_if<!is_same<T_container, string>::value, typename T_container::value_type>::type> ostream& operator<<(ostream &os, const T_container &v) { string sep; for (const T &x : v) os << sep << x, sep = " "; return os; }
#define debug(a) cerr << "(" << #a << ": " << a << ")\n";
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pi;
const int mxN = 5e4+1, oo = 1e9;
const long long MD = 1000001011;
template<long long MOD=MD> struct mdint {
    int d=0;
    mdint () {d=0;}
    mdint (long long _d) : d(_d%MOD){
        if(d<0) d+=MOD;
    };
    friend mdint& operator+=(mdint& a, const mdint& o) {
        a.d+=o.d; if(a.d>=MOD) a.d-=MOD;
        return a;
    }
    friend mdint& operator-=(mdint& a, const mdint& o) {
        a.d-=o.d; if(a.d<0) a.d+=MOD;
        return a;
    }
    friend mdint& operator*=(mdint& a, const mdint& o) {
        return a = mdint((ll)a.d*o.d);
    }
    mdint operator*(const mdint& o) const {
        mdint res = *this;
        res*=o;
        return res;
    }
    mdint operator+(const mdint& o) const {
        mdint res = *this;
        res+=o;
        return res;
    }
    mdint operator-(const mdint& o) const {
        mdint res = *this;
        res-=o;
        return res;
    }
    mdint operator^(long long b) const {
        mdint tmp = 1;
        mdint power = *this;
        while(b) {
            if(b&1) {
                tmp = tmp*power;
            }
            power = power*power;
            b/=2;
        }
        return tmp;
    }
    friend mdint operator/=(mdint& a, const mdint& o) {
        a *= (o^(MOD-2));
        return a;
    }
    mdint operator/(const mdint& o) {
        mdint res = *this;
        res/=o;
        return res;
    }
    bool operator==(const mdint& o) { return d==o.d;}
    bool operator!=(const mdint& o) { return d!=o.d;}
    friend istream& operator>>(istream& c, mdint& a) {return c >> a.d;}
    friend ostream& operator<<(ostream& c, const mdint& a) {return c << a.d;}
};
using  mint = mdint<MD>;
mint pw[mxN];
const mint base = 546575;
void precomp() {
    pw[0]=1;
    for(int i=1;i<mxN;++i) pw[i]=pw[i-1]*base;
}

const int S = 13000019;
struct bloomfilter {
    bitset<S> bs = {};
    vi v;
    bool check(ll i) {
        return bs[i%S] and bs[(i*6755^1244546)%S];
    }
    void clear() {
        for(auto i : v) {
            add(i,0);
        }
        v.clear();
    }
    void add(ll i, bool s=1) {
        if(s) v.push_back(i);
        bs[i%S]=bs[(i*6755^1244546)%S]=s;
    }
} bf[2];

bitset<mxN> vis;
basic_string<int> adj[mxN];
int sz[mxN];
string s;
void dfsz(int at) {
    vis[at]=1;
    sz[at]=1;
    for(int to : adj[at]) if(!vis[to]) {
        dfsz(to);        
        sz[at]+=sz[to];
    }
    vis[at]=0;
}
int LEN;
vector<char> palin = {1};
vector<mint> pref = {0};
int d=1;
bool CHECKING=false;
tuple<bool,bool,int> good() {
    int check = min(d,LEN-d);
    if(d>check) {
        if(!palin[d-check]) return {0,0,0};
    }
    return {true,  d >= (LEN+1 + !CHECKING)/2, (pref.back()- pw[check]*pref[d-check]).d};
}
bool foundLEN=false;
mint b=0;
template<typename F> void dfsD(int at) {
    d++;
    b+=pw[d-1]*s[at];
    pref.push_back(pref.back()*base+s[at]);
    vis[at]=1;
    palin.push_back(pref.back()==b);
    auto [g,big,val] = good();
    F func;
    if(g) func(val,big);
    for(int to : adj[at]) if(!vis[to]) {
        dfsD<F>(to);
    }
    palin.pop_back();
    pref.pop_back();
    vis[at]=0;
    b-=pw[d-1]*s[at];
    d--;
}

int centroid(int at) {
    int total=sz[at], from=-1;
    while(true) {
        bool f=false;
        for(int to : adj[at]) if(to!=from and !vis[to]) {
            if(sz[to]*2>total) {
                from=at;
                at=to;
                f=true;
                break;
            }
        }
        if(!f) return at;
    }
}

bool decomp(int at) {

    dfsz(at);
    int c = centroid(at);
    vis[c]=1;
    for(int to : adj[c]) if(!vis[to]) {
        if(decomp(to)) {
            vis[c]=0;
            return true;
        }
    }
    // now the real work.
    bf[0].add(0);
    for(int to : adj[c]) if(!vis[to]) {
        struct mycheck {
            void operator()(int v, bool big) const {
                if(bf[!big].check(v)) {
                    foundLEN=true;
                }
            }
        };
        struct myadd {
            void operator()(int v, bool big) const {
                bf[big].add(v);
            }
        };
        d=1;
        palin.push_back(1);
        pref.push_back(s[c]);
        CHECKING=true;
        b=s[c];
        dfsD<mycheck>(to);
        palin.pop_back();
        pref.pop_back();
        CHECKING=false;
        d=0;
        b=0;
        dfsD<myadd>(to);

        if(foundLEN) break;
    }
    bf[0].clear();
    bf[1].clear();
    vis[c]=0;
    return foundLEN;
}


int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    precomp();
    int n; cin >> n;
    pref.reserve(n+2);
    palin.reserve(n+2);
    for(auto& b : bf) b.v.reserve(n+2);
    cin >> s;
    for(int i=0;i<n-1;++i) {
        int a,b; cin >> a >> b,--a,--b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    int lo = 0,hi=n/2;
    while(lo<hi) {
        int mid = (lo+hi+1)/2;
        LEN = mid*2;
        foundLEN=0;
        if(decomp(0)) {
            lo = mid;
        } else hi = mid-1;
    }
    int ans=lo*2;
    lo=0,hi = (n-1)/2;
    while(lo<hi) {
        int mid = (lo+hi+1)/2;
        LEN = mid*2+1;
        foundLEN=0;
        if(decomp(0)) {
            lo = mid;
        } else hi = mid-1;
    }
    ans = max(ans,lo*2+1);
    cout << ans << '\n';

}

Subtask #1
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 5204 KB Output is correct
2 Correct 9 ms 5288 KB Output is correct
3 Correct 25 ms 5204 KB Output is correct
4 Correct 37 ms 5204 KB Output is correct
5 Correct 2 ms 5204 KB Output is correct
6 Correct 3 ms 5204 KB Output is correct
7 Correct 3 ms 5204 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1333 ms 9156 KB Output is correct
2 Correct 1799 ms 9220 KB Output is correct
3 Correct 1743 ms 9408 KB Output is correct
4 Correct 1783 ms 9628 KB Output is correct
5 Correct 1792 ms 9756 KB Output is correct
6 Correct 2007 ms 9996 KB Output is correct

Subtask #3
31.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 2028 ms 6908 KB Output is correct
2 Correct 2260 ms 6568 KB Output is correct
3 Correct 2001 ms 6876 KB Output is correct
4 Correct 2534 ms 6980 KB Output is correct
5 Correct 1995 ms 6604 KB Output is correct
6 Correct 1360 ms 6560 KB Output is correct

Subtask #4
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 5204 KB Output is correct
2 Correct 9 ms 5288 KB Output is correct
3 Correct 25 ms 5204 KB Output is correct
4 Correct 37 ms 5204 KB Output is correct
5 Correct 2 ms 5204 KB Output is correct
6 Correct 3 ms 5204 KB Output is correct
7 Correct 3 ms 5204 KB Output is correct
8 Correct 1333 ms 9156 KB Output is correct
9 Correct 1799 ms 9220 KB Output is correct
10 Correct 1743 ms 9408 KB Output is correct
11 Correct 1783 ms 9628 KB Output is correct
12 Correct 1792 ms 9756 KB Output is correct
13 Correct 2007 ms 9996 KB Output is correct
14 Correct 2028 ms 6908 KB Output is correct
15 Correct 2260 ms 6568 KB Output is correct
16 Correct 2001 ms 6876 KB Output is correct
17 Correct 2534 ms 6980 KB Output is correct
18 Correct 1995 ms 6604 KB Output is correct
19 Correct 1360 ms 6560 KB Output is correct
20 Correct 1280 ms 5964 KB Output is correct
21 Correct 1348 ms 5964 KB Output is correct
22 Correct 2110 ms 5964 KB Output is correct
23 Correct 585 ms 6080 KB Output is correct
24 Correct 2131 ms 6796 KB Output is correct
25 Correct 2079 ms 6536 KB Output is correct
26 Correct 2469 ms 6964 KB Output is correct
27 Correct 1957 ms 6048 KB Output is correct
28 Correct 2102 ms 6072 KB Output is correct
29 Correct 2161 ms 6152 KB Output is correct
30 Correct 2672 ms 7336 KB Output is correct
31 Correct 1791 ms 6492 KB Output is correct
32 Correct 1782 ms 7692 KB Output is correct
33 Correct 992 ms 6592 KB Output is correct