oj.uz

Submission #668130

# Submission time Handle Problem Language Result Execution time Memory
668130 2022-12-02T21:10:24 Z jeroenodb Lampice (COCI19_lampice) C++17
110 / 110
 2624 ms 9896 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, 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 5 ms 5204 KB Output is correct
2 Correct 10 ms 5204 KB Output is correct
3 Correct 41 ms 5204 KB Output is correct
4 Correct 36 ms 5204 KB Output is correct
5 Correct 4 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 1213 ms 9120 KB Output is correct
2 Correct 1718 ms 9216 KB Output is correct
3 Correct 1652 ms 9480 KB Output is correct
4 Correct 1977 ms 9600 KB Output is correct
5 Correct 1806 ms 9744 KB Output is correct
6 Correct 2245 ms 9896 KB Output is correct

Subtask #3
31.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 2063 ms 6784 KB Output is correct
2 Correct 2163 ms 6560 KB Output is correct
3 Correct 1882 ms 6988 KB Output is correct
4 Correct 2404 ms 7104 KB Output is correct
5 Correct 1954 ms 6608 KB Output is correct
6 Correct 1361 ms 6604 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 10 ms 5204 KB Output is correct
3 Correct 41 ms 5204 KB Output is correct
4 Correct 36 ms 5204 KB Output is correct
5 Correct 4 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 1213 ms 9120 KB Output is correct
9 Correct 1718 ms 9216 KB Output is correct
10 Correct 1652 ms 9480 KB Output is correct
11 Correct 1977 ms 9600 KB Output is correct
12 Correct 1806 ms 9744 KB Output is correct
13 Correct 2245 ms 9896 KB Output is correct
14 Correct 2063 ms 6784 KB Output is correct
15 Correct 2163 ms 6560 KB Output is correct
16 Correct 1882 ms 6988 KB Output is correct
17 Correct 2404 ms 7104 KB Output is correct
18 Correct 1954 ms 6608 KB Output is correct
19 Correct 1361 ms 6604 KB Output is correct
20 Correct 1195 ms 5960 KB Output is correct
21 Correct 1222 ms 5964 KB Output is correct
22 Correct 2048 ms 5972 KB Output is correct
23 Correct 536 ms 6080 KB Output is correct
24 Correct 2144 ms 6752 KB Output is correct
25 Correct 2091 ms 6536 KB Output is correct
26 Correct 2209 ms 7044 KB Output is correct
27 Correct 1925 ms 6140 KB Output is correct
28 Correct 2050 ms 6132 KB Output is correct
29 Correct 2074 ms 6092 KB Output is correct
30 Correct 2624 ms 7256 KB Output is correct
31 Correct 1790 ms 6476 KB Output is correct
32 Correct 1733 ms 7776 KB Output is correct
33 Correct 1081 ms 6536 KB Output is correct