oj.uz

Submission #668123

# Submission time Handle Problem Language Result Execution time Memory
668123 2022-12-02T20:59:28 Z jeroenodb Lampice (COCI19_lampice) C++17
73 / 110
 2487 ms 9236 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 = 1e9+9;
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 = 123346;
void precomp() {
    pw[0]=1;
    for(int i=1;i<mxN;++i) pw[i]=pw[i-1]*base;
}

const int S = 10000019;
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, F func) {
    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();
    if(g) func(val,big);
    for(int to : adj[at]) if(!vis[to]) {
        dfsD(to,func);
    }
    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]) {
        auto mycheck = [&](int v, bool big) {
            if(bf[!big].check(v)) {
                foundLEN=true;
            }
        };
        auto myadd = [&](int v, bool big) {
            bf[big].add(v);
        };
        d=1;
        palin.push_back(1);
        pref.push_back(s[c]);
        CHECKING=true;
        b=s[c];
        dfsD(to,mycheck);
        palin.pop_back();
        pref.pop_back();
        CHECKING=false;
        d=0;
        b=0;
        dfsD(to,myadd);

        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 4 ms 4436 KB Output is correct
2 Correct 9 ms 4436 KB Output is correct
3 Correct 25 ms 4564 KB Output is correct
4 Correct 37 ms 4564 KB Output is correct
5 Correct 2 ms 4436 KB Output is correct
6 Correct 3 ms 4436 KB Output is correct
7 Correct 2 ms 4436 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1169 ms 8264 KB Output is correct
2 Correct 1642 ms 8560 KB Output is correct
3 Correct 1663 ms 8796 KB Output is correct
4 Correct 1705 ms 8908 KB Output is correct
5 Correct 1772 ms 9016 KB Output is correct
6 Correct 2113 ms 9236 KB Output is correct

Subtask #3
31.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 1942 ms 6064 KB Output is correct
2 Correct 2043 ms 5888 KB Output is correct
3 Correct 1867 ms 6132 KB Output is correct
4 Correct 2369 ms 6224 KB Output is correct
5 Correct 1877 ms 5708 KB Output is correct
6 Correct 1441 ms 5896 KB Output is correct

Subtask #4
0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 4436 KB Output is correct
2 Correct 9 ms 4436 KB Output is correct
3 Correct 25 ms 4564 KB Output is correct
4 Correct 37 ms 4564 KB Output is correct
5 Correct 2 ms 4436 KB Output is correct
6 Correct 3 ms 4436 KB Output is correct
7 Correct 2 ms 4436 KB Output is correct
8 Correct 1169 ms 8264 KB Output is correct
9 Correct 1642 ms 8560 KB Output is correct
10 Correct 1663 ms 8796 KB Output is correct
11 Correct 1705 ms 8908 KB Output is correct
12 Correct 1772 ms 9016 KB Output is correct
13 Correct 2113 ms 9236 KB Output is correct
14 Correct 1942 ms 6064 KB Output is correct
15 Correct 2043 ms 5888 KB Output is correct
16 Correct 1867 ms 6132 KB Output is correct
17 Correct 2369 ms 6224 KB Output is correct
18 Correct 1877 ms 5708 KB Output is correct
19 Correct 1441 ms 5896 KB Output is correct
20 Correct 1151 ms 5320 KB Output is correct
21 Correct 1197 ms 5232 KB Output is correct
22 Correct 1937 ms 5228 KB Output is correct
23 Correct 576 ms 5580 KB Output is correct
24 Correct 2140 ms 6004 KB Output is correct
25 Correct 2083 ms 5836 KB Output is correct
26 Correct 2219 ms 6232 KB Output is correct
27 Correct 1879 ms 5364 KB Output is correct
28 Correct 2092 ms 5456 KB Output is correct
29 Correct 2098 ms 5380 KB Output is correct
30 Incorrect 2487 ms 6476 KB Output isn't correct
31 Halted 0 ms 0 KB -